drm/amd/display: DCN35 set min dispclk to 50Mhz

[Why]

Causes hard hangs when resuming after display off on extended/duplicate
modes

[How]

Set the min dispclk to 50Mhz for DCN35

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Nicholas Susanto <Nicholas.Susanto@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>