usb: gadget: mv_u3d: remove unused headers

none of those headers are used by the driver,
removing them still compiles fine.

Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/mv_u3d_core.c

@@ -30,9 +30,6 @@
 #include <linux/platform_device.h>
 #include <linux/platform_data/mv_usb.h>
 #include <linux/clk.h>
-#include <asm/system.h>
-#include <asm/unaligned.h>
-#include <asm/byteorder.h>
 
 #include "mv_u3d.h"