drm/radeon/kms: add support for msi

Try to enable msi on chips that support it.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 8b60e36..ea3efd7 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -784,6 +784,7 @@
 	const struct firmware *me_fw;	/* all family ME firmware */
 	const struct firmware *pfp_fw;	/* r6/700 PFP firmware */
 	struct r600_blit r600_blit;
+	int msi_enabled; /* msi enabled */
 };
 
 int radeon_device_init(struct radeon_device *rdev,