drm/i915/hpd: Fix mtp_tc_hpd_enable_detection()

Set the MTP TC hotplug bits in the correct register.

Shouldn't matter really as this only gets used for eDP
detection and there should be never eDP on TC ports on
current hw.

Signed-off-by: Ville Syrjälä <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Reviewed-by: Jani Nikula <[e-mail]>

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

···
 {
 	struct intel_display *display = to_intel_display(encoder);
 
-	intel_de_rmw(display, SHOTPLUG_CTL_DDI,
+	intel_de_rmw(display, SHOTPLUG_CTL_TC,
 		     mtp_tc_hotplug_mask(encoder->hpd_pin),
 		     mtp_tc_hotplug_enables(encoder));
 }