input: sensors: remove duplicated regulator enabling

APDS993x sensor driver enable its regulators twice and does not
vote them off correctly.

CRs-fixed: 664168
Change-Id: I5061c4d7d8ca57e4b27f1f6eb7f8becbd7648bfb
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>