drm/amd/display: Do Not Consider DSC if Valid Config Not Found

drm/amd/display: Do Not Consider DSC if Valid Config Not Found

[why]
In the mode validation, mst dsc is considered for bw calculation after
common dsc config is determined. Currently it considered common dsc config
is found if max and min target bpp are non zero which is not accurate. Invalid
max and min target bpp values would not get max_kbps and min_kbps calculated,
leading to falsefully pass a mode that does not have valid dsc parameters
available.

[how]
Use the return value of decide_dsc_bandwidth_range() to determine whether valid
dsc common config is found or not. Prune out modes that do not have valid common
dsc config determined.

Reviewed-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>