drm/amd/display: program k1/k2 divider for virtual signal for DCN32

[Why&How]
When using IGT, kms_bw multi display tests trigger an assert since
we ignore virtual signal type. k1/k2 dividers should be correctly
programmed if VSYNC needs to be correct. Add the appropriate condition
to the if arm to fix this.

Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Brian Chang <Brian.Chang@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>