input: touchpanel: fix long time resume problem

Add regulator func to let TP sleep in deeply when suspend.
If not do it, I2c err will cause a long-time driver recovery when
resume. This err can make current leakage too.

CRs-Fixed: 1069898
Change-Id: I5320b548ed2bd939cde7b96fa1f71d196ec64a47
Signed-off-by: Jin Fu <jinf@codeaurora.org>