msm: mdss: Add error checking for incorrect state during HDMI power on/off

HDMI power on should not be permitted if hpd is not initialized.
Similarly HDMI power off should be skipped if power is not on.
Add proper checking for above state conditions.

CRs-Fixed: 417959
Change-Id: I9470c6d818adc403de05c25a7e96c8ab1c8a43fd
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>