ARM: dts: bcm2837-rpi-3-b: Use consistent label for HDMI hotplug

This make the GPIO label for HDMI hotplug more consistent to the other
boards.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

arch/arm/boot/dts/bcm2837-rpi-3-b.dts

@@ -39,7 +39,7 @@ expgpio: gpio {
 				  "WL_ON",
 				  "STATUS_LED",
 				  "LAN_RUN",
-				  "HPD_N",
+				  "HDMI_HPD_N",
 				  "CAM_GPIO0",
 				  "CAM_GPIO1",
 				  "PWR_LOW_N";