USB: Squash checkpatch warnings in usb_kbd.c

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Remy Bohmer <linux@bohmer.net>
Cc: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>

Rebased to current code.

Signed-off-by: Wolfgang Denk <wd@denx.de>