drm/i915: Enable SandyBridge blitter ring

Based on an original patch by Zhenyu Wang, this initializes the BLT ring for
SandyBridge and enables support for user execbuffers.

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
index e41c74f..8c641be 100644
--- a/include/drm/i915_drm.h
+++ b/include/drm/i915_drm.h
@@ -286,6 +286,7 @@
 #define I915_PARAM_HAS_PAGEFLIPPING	 8
 #define I915_PARAM_HAS_EXECBUF2          9
 #define I915_PARAM_HAS_BSD		 10
+#define I915_PARAM_HAS_BLT		 11
 
 typedef struct drm_i915_getparam {
 	int param;
@@ -627,8 +628,11 @@
 	__u32 num_cliprects;
 	/** This is a struct drm_clip_rect *cliprects */
 	__u64 cliprects_ptr;
+#define I915_EXEC_RING_MASK              (7<<0)
+#define I915_EXEC_DEFAULT                (0<<0)
 #define I915_EXEC_RENDER                 (1<<0)
-#define I915_EXEC_BSD                    (1<<1)
+#define I915_EXEC_BSD                    (2<<0)
+#define I915_EXEC_BLT                    (3<<0)
 	__u64 flags;
 	__u64 rsvd1;
 	__u64 rsvd2;