MIPS: BCM47XX: move constant array from stack

Move the possible nvram sizes from the stack into the data segment

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6044/