msm: mdss: hdmi: reset phy on panel power on

HDMI Tx core can be configured with multiple resolutions with
different pixel clocks. This needs PHY/PLL to be configured
with different settings. Reset PHY/PLL on every power on before
configuring new PHY settings to avoid any PLL lock issues.

Change-Id: I564305730105f3e54fbb504c20cce5b2eb9039b1
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>