We adjusted the BO flags for USWC handling, but those never took effect
because the placement was passed in instead of generated inside this
function.

v2: better commit message

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>