drm/amd/display: fix dcn3.1x mode validation on high bandwidth config

drm/amd/display: fix dcn3.1x mode validation on high bandwidth config

[why]
1. correct dram_channel_width (was hard coded to 4 for 32bit)
2. use dm's is_hvm_enable status flag for hostvm_en input for dml.
3. add a function to override to all dcn3.1x.

Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>