drm/i915: Use alphabetical names for sprites

Add sprite_name() macro which should be used with the kind of sprites
that are fixed to pipes (gen4.5+).

Also use dev_priv->num_plane to calculate the sprite index insted
assuming two sprites per pipe. This should make it print the right
name.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -76,6 +76,8 @@ enum plane {
 };
 #define plane_name(p) ((p) + 'A')
 
+#define sprite_name(p, s) ((p) * dev_priv->num_plane + (s) + 'A')
+
 enum port {
 	PORT_A = 0,
 	PORT_B,

drivers/gpu/drm/i915/intel_display.c

@@ -1302,8 +1302,8 @@ static void assert_sprites_disabled(struct drm_i915_private *dev_priv,
 		reg = SPCNTR(pipe, i);
 		val = I915_READ(reg);
 		WARN((val & SP_ENABLE),
-		     "sprite %d assertion failure, should be off on pipe %c but is still active\n",
-		     pipe * 2 + i, pipe_name(pipe));
+		     "sprite %c assertion failure, should be off on pipe %c but is still active\n",
+		     sprite_name(pipe, i), pipe_name(pipe));
 	}
 }
 
@@ -9051,8 +9051,8 @@ void intel_modeset_init(struct drm_device *dev)
 		for (j = 0; j < dev_priv->num_plane; j++) {
 			ret = intel_plane_init(dev, i, j);
 			if (ret)
-				DRM_DEBUG_KMS("pipe %c plane %d init failed: %d\n",
-					      pipe_name(i), j, ret);
+				DRM_DEBUG_KMS("pipe %c sprite %c init failed: %d\n",
+					      pipe_name(i), sprite_name(i, j), ret);
 		}
 	}