panel-minnow: Disable m4sensorhub code for mapphone devices.

Change-Id: I31e371985f33d2df96f948f8c0e9b5a9bd29b04b
Disable CONFIG_HAS_AMBIENTMODE for non-sensorhub devices.

This also requires another #ifdef in panel-minnow to fix usage of
DISPLAY_AMBIENT_OFF which is only available when CONFIG_HAS_AMBIENTMODE
is enabled.

Change-Id: I4ef06c87c599279e4365cc77443620f4ad0327cb
akm8973_akmd: Fixed "err" being undefined in one case.

Change-Id: Ie757d2f7b9e06ef92cca3f2629532da5d2c51cfa