drm/edid: Iterate through all DispID ext blocks

Apparently there are EDIDs in the wild with multiple DispID extension
blocks. Iterate through them all.

In one particular case the tile information is specicied in the
second DispID ext block, and since the current parser only looks
at the first DispID ext block we don't notice that we're dealing
with a tiled display.

While at it change a few functions to return void since we have
no use for the errno.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/27


Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200527130310.27099-2-ville.syrjala@linux.intel.com


Reviewed-by: José Roberto de Souza <jose.souza@intel.com>