drm/i915: Configure TRANSCONF just the once with bigjoiner

Let's not configure the single transcoder's TRANSCONF multiple
times with bigjoiner. No real harm I suppose but since we already
have the bigjoiner if statement directly above might as well suck
this in there and skip the redundant programming.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210913144440.23008-11-ville.syrjala@linux.intel.comReviewed-by: Manasi Navare <manasi.d.navare@intel.com>

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

@@ -3215,10 +3215,9 @@ static void hsw_crtc_enable(struct intel_atomic_state *state,
 						     &new_crtc_state->fdi_m_n, NULL);
 
 		hsw_set_frame_start_delay(new_crtc_state);
-	}
 
-	if (!transcoder_is_dsi(cpu_transcoder))
 		hsw_set_transconf(new_crtc_state);
+	}
 
 	crtc->active = true;