drm/amdgpu: enable runtime pm on vega10 when noretry=0

The failures with ROCm only happen with noretry=1, so
enable runtime pm when noretry=0 (the current default).

Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>