drm: Convert to using %pOFn instead of device_node.name

In preparation to remove the node name pointer from struct device_node,
convert printf users to use the %pOFn format specifier.

For drm_modes.c, the full node path is already printed out, so printing
just the node name a 2nd time is redundant and can be removed.

Cc: Gustavo Padovan <[e-mail]>
Cc: Maarten Lankhorst <[e-mail]>
Cc: Sean Paul <[e-mail]>
Cc: David Airlie <[e-mail]>
Acked-by: Rob Clark <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Rob Herring <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_modes.c

···
 	if (bus_flags)
 		drm_bus_flags_from_videomode(&vm, bus_flags);
 
-	pr_debug("%pOF: got %dx%d display mode from %s\n",
-		np, vm.hactive, vm.vactive, np->name);
+	pr_debug("%pOF: got %dx%d display mode\n",
+		np, vm.hactive, vm.vactive);
 	drm_mode_debug_printmodeline(dmode);
 
 	return 0;

drivers/gpu/drm/msm/hdmi/hdmi.c

···
 	hdmi_cfg = (struct hdmi_platform_config *)
 			of_device_get_match_data(dev);
 	if (!hdmi_cfg) {
-		dev_err(dev, "unknown hdmi_cfg: %s\n", of_node->name);
+		dev_err(dev, "unknown hdmi_cfg: %pOFn\n", of_node);
 		return -ENXIO;
 	}