drm/i915: Use enum pipe instead of crtc index to track active pipes

We may need to eliminate the crtc->index == pipe assumptions from
the code to support arbitrary pipes being fused off. Start that by
switching some bitmasks over to using pipe instead of the crtc index.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190821173033.24123-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 048896b..ba3f6d8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1468,7 +1468,7 @@ struct drm_i915_private {
 	 */
 	struct mutex dpll_lock;
 
-	unsigned int active_crtcs;
+	u8 active_pipes;
 	/* minimum acceptable cdclk for each pipe */
 	int min_cdclk[I915_MAX_PIPES];
 	/* minimum acceptable voltage level for each pipe */