MIPS: BCM47XX: use common error codes in nvram reads

Instead of using our own error codes use some common codes.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4739/
Signed-off-by: John Crispin <blogic@openwrt.org>
3 files changed