drm/radeon: include radeon_asic.h in the asic specific files

In essence this creates a home for all asic specific declarations in
radeon_asic.h

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r520.c b/drivers/gpu/drm/radeon/r520.c
index 2b8a5dd..f6d8541 100644
--- a/drivers/gpu/drm/radeon/r520.c
+++ b/drivers/gpu/drm/radeon/r520.c
@@ -27,6 +27,7 @@
  */
 #include "drmP.h"
 #include "radeon.h"
+#include "radeon_asic.h"
 #include "atom.h"
 #include "r520d.h"