ANDROID: usb: gadget: function: Fix Coding Style

Fix warning by checkpatch.pl:
Prefer 'unsigned int' to bare use of 'unsigned'

Patch applied by running fix inplace capability of checkpatch:
checkpatch.pl -f *.[ch] --types UNSPECIFIED_INT --fix-inplace

Change-Id: I2ba09a70e3a748ea8440f77d5c8e0349db248d49
Signed-off-by: Anson Jacob <ansonjacob.aj@gmail.com>