this reverts drivers/tty/serial/8250/8250_mtk.c back to the v5.17 version
as otherwise it breaks bluetooth on mt8183 kukui devices

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 54051ec7b499..fb65dc601b23 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -37,7 +37,6 @@
 #define MTK_UART_IER_RTSI	0x40	/* Enable RTS Modem status interrupt */
 #define MTK_UART_IER_CTSI	0x80	/* Enable CTS Modem status interrupt */
 
-#define MTK_UART_EFR		38	/* I/O: Extended Features Register */
 #define MTK_UART_EFR_EN		0x10	/* Enable enhancement feature */
 #define MTK_UART_EFR_RTS	0x40	/* Enable hardware rx flow control */
 #define MTK_UART_EFR_CTS	0x80	/* Enable hardware tx flow control */
@@ -54,9 +53,6 @@
 #define MTK_UART_TX_TRIGGER	1
 #define MTK_UART_RX_TRIGGER	MTK_UART_RX_SIZE
 
-#define MTK_UART_XON1		40	/* I/O: Xon character 1 */
-#define MTK_UART_XOFF1		42	/* I/O: Xoff character 1 */
-
 #ifdef CONFIG_SERIAL_8250_DMA
 enum dma_rx_status {
 	DMA_RX_START = 0,
@@ -173,7 +169,7 @@ static void mtk8250_dma_enable(struct uart_8250_port *up)
 		   MTK_UART_DMA_EN_RX | MTK_UART_DMA_EN_TX);
 
 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-	serial_out(up, MTK_UART_EFR, UART_EFR_ECB);
+	serial_out(up, UART_EFR, UART_EFR_ECB);
 	serial_out(up, UART_LCR, lcr);
 
 	if (dmaengine_slave_config(dma->rxchan, &dma->rxconf) != 0)
@@ -236,7 +232,7 @@ static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
 	int lcr = serial_in(up, UART_LCR);
 
 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-	serial_out(up, MTK_UART_EFR, UART_EFR_ECB);
+	serial_out(up, UART_EFR, UART_EFR_ECB);
 	serial_out(up, UART_LCR, lcr);
 	lcr = serial_in(up, UART_LCR);
 
@@ -245,7 +241,7 @@ static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
 		serial_out(up, MTK_UART_ESCAPE_DAT, MTK_UART_ESCAPE_CHAR);
 		serial_out(up, MTK_UART_ESCAPE_EN, 0x00);
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-		serial_out(up, MTK_UART_EFR, serial_in(up, MTK_UART_EFR) &
+		serial_out(up, UART_EFR, serial_in(up, UART_EFR) &
 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK)));
 		serial_out(up, UART_LCR, lcr);
 		mtk8250_disable_intrs(up, MTK_UART_IER_XOFFI |
@@ -259,8 +255,8 @@ static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 
 		/*enable hw flow control*/
-		serial_out(up, MTK_UART_EFR, MTK_UART_EFR_HW_FC |
-			(serial_in(up, MTK_UART_EFR) &
+		serial_out(up, UART_EFR, MTK_UART_EFR_HW_FC |
+			(serial_in(up, UART_EFR) &
 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
 
 		serial_out(up, UART_LCR, lcr);
@@ -274,12 +270,12 @@ static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 
 		/*enable sw flow control */
-		serial_out(up, MTK_UART_EFR, MTK_UART_EFR_XON1_XOFF1 |
-			(serial_in(up, MTK_UART_EFR) &
+		serial_out(up, UART_EFR, MTK_UART_EFR_XON1_XOFF1 |
+			(serial_in(up, UART_EFR) &
 			(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
 
-		serial_out(up, MTK_UART_XON1, START_CHAR(port->state->port.tty));
-		serial_out(up, MTK_UART_XOFF1, STOP_CHAR(port->state->port.tty));
+		serial_out(up, UART_XON1, START_CHAR(port->state->port.tty));
+		serial_out(up, UART_XOFF1, STOP_CHAR(port->state->port.tty));
 		serial_out(up, UART_LCR, lcr);
 		mtk8250_disable_intrs(up, MTK_UART_IER_CTSI|MTK_UART_IER_RTSI);
 		mtk8250_enable_intrs(up, MTK_UART_IER_XOFFI);
@@ -293,10 +289,10 @@ static void
 mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
 			struct ktermios *old)
 {
-	static const unsigned short fraction_L_mapping[] = {
+	unsigned short fraction_L_mapping[] = {
 		0, 1, 0x5, 0x15, 0x55, 0x57, 0x57, 0x77, 0x7F, 0xFF, 0xFF
 	};
-	static const unsigned short fraction_M_mapping[] = {
+	unsigned short fraction_M_mapping[] = {
 		0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 3
 	};
 	struct uart_8250_port *up = up_to_u8250p(port);