msm: mdss: hdmi: fall back to legacy block when CEA block is bad

In case of CEA extension block is not correct or corrupted, fall
back to block 0 to read the resolutions supported.

Change-Id: I2b63ff1f918b3ece89ab35eb4a64d4ac96aaeabe
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>