msm_fb: HDMI: Start HDCP authentication only on device open

Currently HDCP authentication is started for a default resolution
upon HPD connection event. With this change, HDCP authentication
is only triggered after the HDMI interface has been configured for
an appropriate resolution following the call to open the HDMI device.

CRs-Fixed: 368865
Change-Id: I7b9ce85aed989b78b448bff6a545a194dfed5b1d
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>