usb: musb: Allow multiple glue layers to be built in

There's no reason any longer to keep it as a choice now that
the IO access has been fixed.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/Kconfig

@@ -58,8 +58,7 @@ config USB_MUSB_DUAL_ROLE
 
 endchoice
 
-choice
-	prompt "Platform Glue Layer"
+comment "Platform Glue Layer"
 
 config USB_MUSB_DAVINCI
 	tristate "DaVinci"
@@ -101,8 +100,6 @@ config USB_MUSB_JZ4740
 	depends on USB_MUSB_GADGET
 	depends on USB_OTG_BLACKLIST_HUB
 
-endchoice
-
 config USB_MUSB_AM335X_CHILD
 	tristate