There's no need to handle complicated scenarios or debug log when
filtering blocks that have already been identified as invalid. Simplify
by adding an edid_block_valid() helper that operates on const data and
prints nothing.

(Finally, here's the justification for the previously added separate
edid_block_status_valid() function!)

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/aa25131c3454c7dbc1e8fdb46549f3787bdf6354.1648752228.git.jani.nikula@intel.com