drm/radeon: call drm_edid_to_eld when we update the edid

This needs to be done to update some of the fields in
the connector structure used by the audio code.

Noticed by several users on irc.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org