drm/vc4: Add another reg to HDMI debug dumping.

This is also involved in the HDMI setup sequence so it's nice to see
it.

Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 6e55760..56272ca 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -95,6 +95,7 @@
 	HDMI_REG(VC4_HDMI_SW_RESET_CONTROL),
 	HDMI_REG(VC4_HDMI_HOTPLUG_INT),
 	HDMI_REG(VC4_HDMI_HOTPLUG),
+	HDMI_REG(VC4_HDMI_RAM_PACKET_CONFIG),
 	HDMI_REG(VC4_HDMI_HORZA),
 	HDMI_REG(VC4_HDMI_HORZB),
 	HDMI_REG(VC4_HDMI_FIFO_CTL),