drm/i915: Add functions to emit register offsets to the ring

When register type safety happens, we can't just try to emit the
register itself to the ring. Instead we'll need to extract the
offset from it first. Add some convenience functions that will do
that.

v2: Convert MOCS setup too

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446672017-24497-20-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -443,6 +443,11 @@ static inline void intel_ring_emit(struct intel_engine_cs *ring,
 	iowrite32(data, ringbuf->virtual_start + ringbuf->tail);
 	ringbuf->tail += 4;
 }
+static inline void intel_ring_emit_reg(struct intel_engine_cs *ring,
+				       u32 reg)
+{
+	intel_ring_emit(ring, reg);
+}
 static inline void intel_ring_advance(struct intel_engine_cs *ring)
 {
 	struct intel_ringbuffer *ringbuf = ring->buffer;