drm/i915: use drm_debug_enabled() to check for debug categories

Allow better abstraction of the drm_debug global variable in the
future. No functional changes.

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Sean Paul <sean@poorly.run>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e94fe4977c5b8cac68556318be81f8e422e973fd.1572258936.git.jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 3622344..08255a9 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5307,7 +5307,7 @@ skl_print_wm_changes(struct intel_atomic_state *state)
 	struct intel_crtc *crtc;
 	int i;
 
-	if ((drm_debug & DRM_UT_KMS) == 0)
+	if (!drm_debug_enabled(DRM_UT_KMS))
 		return;
 
 	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,