msm: mdss: add support for Cx iPeak limit management

Every client driver participating in Cx iPeak mitigation
scheme need to-

1)Register to Cxipeak driver.
2)Set vote for TCSR block before clock switch to fmax-threshold
or above through cxipeak API.
3)Remove vote for TCSR block after clock switch to below
fmax-threshold through cxipeak API.

Changes were made to address the same from mdss driver.

Change-Id: I21cba823563d3788ab03c885703f781b5d3e936a
Signed-off-by: Raviteja Tamatam <travitej@codeaurora.org>