drm/edid: convert drm_detect_hdmi_monitor() to use cea db iter

Iterate through all CTA data blocks, not just the first CTA extension.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b867e7b628189d2f8fa7eac5b9aa701892724711.1651569697.git.jani.nikula@intel.com