drm/amdgpu: parse UMA size-getting/setting bits in ATCS mask

drm/amdgpu: parse UMA size-getting/setting bits in ATCS mask

The capabilities of getting and setting VRAM carveout size are exposed
in the ATCS mask. Parse and store these capabilities for future use.

Co-developed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Yo-Jung Leo Lin (AMD) <Leo.Lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>