msm: sde: support rotator power enable through rsc

Attempt to enable the rotator footswitch through the
sde RSC driver, if available. The driver will fall
back to the original method of controlling the
regulators directly if it fails to register itself
as an RSC client.

CRs-Fixed: 2041710
Change-Id: I522df252153cef66ac57ab457eb0a498e43c7594
Signed-off-by: Clarence Ip <cip@codeaurora.org>