input: sensor: add check if regulator is valid before releasing it

Sensor regulator could be still invalid at the time of a system
suspend, this change is to avoid freeing NULL regulators under such
occasion.

Change-Id: Ia520b2516b43feaa3fbbbe30628cc47ee7fad96a
Signed-off-by: Wentao Xu <wentaox@codeaurora.org>
2 files changed