drm/msm: update msg log level for edid cea ext check

Update the message log level to sde_debug from sde_error
to avoid printing the invalid error message during edid,
without cea extension, parsing for connectors.

Change-Id: I252f786691b183ba88e5b19a90c6a3db914dcd7c
Signed-off-by: Govinda Rajulu Chenna <gchenna@codeaurora.org>