drm/i915: Drop crtc NULL check from intel_crtc_active()

intel_crtc_active() is never called with a NULL crtc. Drop
the redundant NULL check.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231207193441.20206-5-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/i9xx_wm.c

@@ -608,7 +608,7 @@ static bool intel_crtc_active(struct intel_crtc *crtc)
 	 * crtc->state->active once we have proper CRTC states wired up
 	 * for atomic.
 	 */
-	return crtc && crtc->active && crtc->base.primary->state->fb &&
+	return crtc->active && crtc->base.primary->state->fb &&
 		crtc->config->hw.adjusted_mode.crtc_clock;
 }