usb: dwc3: Fix a compilation error with the edison defconfig

The error is:
In file included from include/part.h:10:0,
                 from include/usb.h:18,
                 from include/linux/usb/gadget.h:22,
                 from drivers/usb/dwc3/ep0.c:20:
include/ide.h:62:14: error: unknown type name ‘uchar’
 void ide_led(uchar led, uchar status);

Fixing it by including common.h that defines the uchar type.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

drivers/usb/dwc3/ep0.c

@@ -12,7 +12,7 @@
  *
  * commit c00552ebaf : Merge 3.18-rc7 into usb-next
  */
-
+#include <common.h>
 #include <linux/kernel.h>
 #include <linux/list.h>