USB: core: Add input prompt and help text for USB_OTG config

bd6882 commit (usb: gadget: fix Kconfig warning) removes
the duplicate USB_OTG config from gadget/Kconfig.  But
does not copy the input prompt and help text to the original
config defined in core/Kconfig. Add them now.

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/Kconfig

@@ -107,11 +107,19 @@ config USB_SUSPEND
 	  If you are unsure about this, say N here.
 
 config USB_OTG
-	bool
+	bool "OTG support"
 	depends on USB && EXPERIMENTAL
 	depends on USB_SUSPEND
 	default n
+	help
+	  The most notable feature of USB OTG is support for a
+	  "Dual-Role" device, which can act as either a device
+	  or a host. The initial role is decided by the type of
+	  plug inserted and can be changed later when two dual
+	  role devices talk to each other.
 
+	  Select this only if your board has Mini-AB/Micro-AB
+	  connector.
 
 config USB_OTG_WHITELIST
 	bool "Rely on OTG Targeted Peripherals List"