drm/amd/display: Simplify same effect if/else blocks

The if / else block code has same effect irrespective of the logical
evaluation.  Hence, simply the implementation by removing the unnecessary
conditional evaluation. While at it, also fix the long line checkpatch
complaint. Issue identified using cond_no_effect.cocci Coccinelle
semantic patch script.

Fixes: 9114b55f ("drm/amd/display: Fix SubVP control flow in the MPO context")
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Deepak R Varma <drv@mailo.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>