msm: ipa4: vote for IPA_PC note after uC is loaded

To enable the ipa power collapse, we need to enable rpmh and uC
handshaking so that uC can do the register retention. The logic
is missing for APQ target.

Change-Id: Ife381bc4936b07558a19b29db313ee1ebe06bd2c
Signed-off-by: Bojun Pan <bojunp@codeaurora.org>