msm_fb: HDMI: Fix handling of HDMI PLL software reset

Whenever a software reset is asserted on the HDMI PLL, we should
wait for short time to wait for the PLL calibration to be
successful before checking to see if the PLL is locked.

CRs-Fixed: 378044
Change-Id: I736e2eff4dce778ba3e305d9461cdedc607156ae
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>