MIPS: BCM63XX: fix revision ID width

The REVID is only 8 bit wide.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5007/
Acked-by: John Crispin <blogic@openwrt.org>
4 files changed