drm/i915/tc: Delete bogus NULL check in intel_ddi_encoder_destroy()

The "digi_port" pointer can't be NULL and we have already dereferenced
it so checking for NULL is not necessary.  Delete the check.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211004103737.GC25015@kili

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

@@ -3937,7 +3937,6 @@ static void intel_ddi_encoder_destroy(struct drm_encoder *encoder)
 	intel_display_power_flush_work(i915);
 
 	drm_encoder_cleanup(encoder);
-	if (dig_port)
 	kfree(dig_port->hdcp_port_data.streams);
 	kfree(dig_port);
 }