usb: udc: add udc.h include file

Move common definitions to udc.h
This allows musb_udc.h to be removed as well.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
diff --git a/drivers/serial/usbtty.h b/drivers/serial/usbtty.h
index e243a8e..819dec6 100644
--- a/drivers/serial/usbtty.h
+++ b/drivers/serial/usbtty.h
@@ -16,8 +16,6 @@
 #include <usb/mpc8xx_udc.h>
 #elif defined(CONFIG_OMAP1510)
 #include <usb/omap1510_udc.h>
-#elif defined(CONFIG_MUSB_UDC)
-#include <usb/musb_udc.h>
 #elif defined(CONFIG_CPU_PXA27X)
 #include <usb/pxa27x_udc.h>
 #elif defined(CONFIG_DW_UDC)
@@ -26,6 +24,7 @@
 #include <usb/mv_udc.h>
 #endif
 
+#include <usb/udc.h>
 #include <version.h>
 
 /* If no VendorID/ProductID is defined in config.h, pretend to be Linux