mediatek: sprout: fail to enable tethering

All kinds of tethering fail due to no ip_forward proc
file and incorrect kernel config about NAT. So we find
the root cause and fix it by removing duplicated proc
entry and modifying kernel config.

Change-Id: I6f13db0a1bb3e7c416f046074208cc239da121cf
Signed-off-by: Cylen Yao <cylen.yao@mediatek.com>
3 files changed