drm/amd/display: Add FAMS validation before trying to use it

drm/amd/display: Add FAMS validation before trying to use it

[ Upstream commit e3416e872f84086667df21daf166506fab97358d ]

To ensure that FAMS can be used, DC must check if there is VRR support.
This commit adds the required configuration to ensure FAMS can be executed in the target system.

Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Stable-dep-of: 2a9482e55968 ("drm/amd/display: Prevent vtotal from being set to 0")
Signed-off-by: Sasha Levin <sashal@kernel.org>