winsys/amdgpu: Process RADEON_FLAG_* independently from RADEON_DOMAIN_*

winsys/amdgpu: Process RADEON_FLAG_* independently from RADEON_DOMAIN_*

In particular, AMDGPU_GEM_CREATE_CPU_GTT_USWC can affect even BOs created
in VRAM if they get evicted to GTT. In general there's no need to
restrict any of the flags to any particular domains.

Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>