i915/drm: provide compat defines for userspace for certain struct members.

Painfully userspace started using new names that were never actually to be
used from the external repo.

Also fill out the gaps in the structure for old/new userspace compat

Add compat defines for these structs.
Signed-off-by: NDave Airlie <airlied@redhat.com>

include/drm/i915_drm.h

@@ -113,8 +113,31 @@ typedef struct _drm_i915_sarea {
 	int pipeB_y;
 	int pipeB_w;
 	int pipeB_h;
+
+	/* fill out some space for old userspace triple buffer */
+	drm_handle_t unused_handle;
+	uint32_t unused1, unused2, unused3;
+
+	/* buffer object handles for static buffers. May change
+	 * over the lifetime of the client.
+	 */
+	uint32_t front_bo_handle;
+	uint32_t back_bo_handle;
+	uint32_t unused_bo_handle;
+	uint32_t depth_bo_handle;
+
 } drm_i915_sarea_t;
 
+/* due to userspace building against these headers we need some compat here */
+#define planeA_x pipeA_x
+#define planeA_y pipeA_y
+#define planeA_w pipeA_w
+#define planeA_h pipeA_h
+#define planeB_x pipeB_x
+#define planeB_y pipeB_y
+#define planeB_w pipeB_w
+#define planeB_h pipeB_h
+
 /* Flags for perf_boxes
  */
 #define I915_BOX_RING_EMPTY    0x1