MIPS: BCM47XX: Fix detecting Microsoft MN-700 & Asus WL500G

Since the day of adding this code it was broken. We were iterating over
a wrong array and checking for wrong NVRAM entry.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: https://patchwork.linux-mips.org/patch/9654/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>