msm: mdss: Control histogram intr and clk in suspend cases

Histogram interrupts, and clocks used to handle interrupts, need to be
enabled in sync with histogram requests. To ensure that these interrupts
and clocks are disabled when screen is suspended or not updating, a control
structure is introduced that allows for these resources to be gated by
specifying transitions from when they should and should not be active.

CRs-Fixed: 568049
Change-Id: I77a50085ee38de597092c273c7ce9974c7bb29c3
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>