drm/radeon/kms: fix gart setup on fusion parts (v2)

Out of the entire GART/VM subsystem, the hw designers changed
the location of 3 regs.

v2: airlied: add parameter for userspace to work from.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 871df03..bd58af6 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -234,6 +234,9 @@
 			return -EINVAL;
 		}
 		break;
+	case RADEON_INFO_FUSION_GART_WORKING:
+		value = 1;
+		break;
 	default:
 		DRM_DEBUG_KMS("Invalid request %d\n", info->request);
 		return -EINVAL;