msm: mdss_fb: Do not issue runtime suspend/resume for HDMI primary

When HDMI is primary, do not issue runtime suspend and resume events
to HDMI interface. Runtime suspend/resume may get triggered with cable
connect/disconnect when HDMI is primary which will result in unnecessary
power on/off of HPD module.

Change-Id: I6c0c9eb85832717be538b3fbf7583b1e4a5c10d5
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>