ARM: OMAP: USB: remove unnecessary sideways include

Remove the include of mach-omap2/common.h from plat-omap/usb.c.  It
appears to be unneeded.  Removing it also resolves the sparse warning:

arch/arm/plat-omap/../mach-omap2/common.h:183:12: warning: symbol 'omap_intc_of_init' was not declared. Should it be static?
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/plat-omap/usb.c

@@ -31,8 +31,6 @@
 
 #include <mach/hardware.h>
 
-#include "../mach-omap2/common.h"
-
 #ifdef	CONFIG_ARCH_OMAP_OTG
 
 void __init