Convert drm_find_cea_extension() to a predicate function to check if the
EDID has a CTA extension or a DisplayID CTA data block. This is mainly
to avoid adding new users that only find the first CTA extension.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a5bf228942e6bd0fc70d5cf7a14c249a14a7afcd.1651569697.git.jani.nikula@intel.com