input: sensors: lis3dh driver get regulator multiple times

Device driver does not need to request regulator each time it power
on the device, it only need to vote on/off regulators and release
regulators before exit.

Change-Id: I01c4e1a9ee48495cdab965a4fb99dae3b01b57a3
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>