input: sensors: akm8963 doesn't vote regulators off on CDP

The driver doesn't vote regulators off when sensor device is
not detected.

CRs-fixed: 669309
Change-Id: Ie8a93ddc8b89b3ef9d4a3dfa6b4dae17c13ab76e
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>