clk: msm: hdmi: add support for live programming of HDMI PLL

Clock recovery and dynamic resolution change require changing
HDMI clock rate while HDMI PLL is on. There are two paths while
clock is changed, one is atomic update which doesn't require
PLL tear down, the other is when clock rate change is too big
and a full PLL tear down is needed.

CRs-Fixed: 1086894
Change-Id: Ia202e0aee09f506a7bbe4e13702f30dee119ce8e
Signed-off-by: Ray Zhang <rayz@codeaurora.org>