drm/amd/display: update infoframe after dig fe is turned on (v2)

[Why]
The AVI infoframe is incorrectly programmed on DCN1/2 when enabling a
stream - causing the wrong pixel encoding to be used for display.

This is because the AVI infoframe is programmed before the DIG BE is
connected to the FE and turned on, so enabling the AFMT block doesn't
actually work and the registers subsequently can't be written to.

[How]
Program the infoframe *after* turning on the DIG FE. This was the
behavior previously used but it was incorrectly reverted
when adding the DCN2 HW sequencer code.

v2: Don't call update_info_frame twice

Fixes: 7ed4e635

 ("drm/amd/display: Add DCN2 HW Sequencer and Resource")

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>