usbip: move usbip userspace code out of staging

At this point, USB/IP userspace code is fully functional
and can be moved out of staging.

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/usb/usbip/libsrc/sysfs_utils.c

@@ -0,0 +1,31 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "sysfs_utils.h"
+#include "usbip_common.h"
+
+int write_sysfs_attribute(const char *attr_path, const char *new_value,
+			  size_t len)
+{
+	int fd;
+	int length;
+
+	fd = open(attr_path, O_WRONLY);
+	if (fd < 0) {
+		dbg("error opening attribute %s", attr_path);
+		return -1;
+	}
+
+	length = write(fd, new_value, len);
+	if (length < 0) {
+		dbg("error writing to attribute %s", attr_path);
+		close(fd);
+		return -1;
+	}
+
+	close(fd);
+
+	return 0;
+}