DCB: fix kconfig option

Since the netlink option for DCB is necessary to actually be useful,
simplified the Kconfig option.  In addition, added useful help text for the
Kconfig option.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dcb/Kconfig

@@ -1,12 +1,22 @@
 config DCB
-        tristate "Data Center Bridging support"
-
-config DCBNL
-	bool "Data Center Bridging netlink interface support"
-	depends on DCB
+	bool "Data Center Bridging support"
 	default n
 	---help---
-	  This option turns on the netlink interface
-	  (dcbnl) for Data Center Bridging capable devices.
+	  This enables support for configuring Data Center Bridging (DCB)
+	  features on DCB capable Ethernet adapters via rtnetlink.  Say 'Y'
+	  if you have a DCB capable Ethernet adapter which supports this
+	  interface and you are connected to a DCB capable switch.
+
+	  DCB is a collection of Ethernet enhancements which allow DCB capable
+	  NICs and switches to support network traffic with differing
+	  requirements (highly reliable, no drops vs. best effort vs. low
+	  latency) to co-exist on Ethernet.
+
+	  DCB features include:
+	    Enhanced Transmission Selection (aka Priority Grouping) - provides a
+	      framework for assigning bandwidth guarantees to traffic classes.
+	    Priority-based Flow Control (PFC) - a MAC control pause frame which
+	      works at the granularity of the 802.1p priority instead of the
+	      link (802.3x).
 
 	  If unsure, say N.

net/dcb/dcbnl.c

@@ -48,7 +48,7 @@
  */
 
 MODULE_AUTHOR("Lucy Liu, <lucy.liu@intel.com>");
-MODULE_DESCRIPTION("Data Center Bridging generic netlink interface");
+MODULE_DESCRIPTION("Data Center Bridging netlink interface");
 MODULE_LICENSE("GPL");
 
 /**************** DCB attribute policies *************************************/