msm: mdss: do not do phy reset when HDMI power off

Do not need to do HDMI PHY reset here, because will do
that when HDMI cable connected again in HDMI mode setting
function.

Change-Id: Ifae7c35f72a9008980c207e0806ab7aaa57dfe07
Signed-off-by: Yuan Zhao <yzhao@codeaurora.org>