ARM64: dts: meson: add comments with the GPIO for the PHY interrupts

Currently one has to look/calculate the GPIO for the PHY interrupts
manually. Add a comment for the existing PHY interrupt lines to make it
easier to find out which GPIO is used.
This is done using the following calculation:
- number of GPIO AO pins (14 on GXBB: GPIOAO_0..13)
- add the offset of the pin which is used for the interrupt (for example
  GPIOZ_15 = 15 on Odroid-C2)
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-By: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-gxbb-nanopi-k2.dts

@@ -169,6 +169,7 @@ eth_phy0: ethernet-phy@0 {
 			/* Realtek RTL8211F (0x001cc916) */
 			reg = <0>;
 			interrupt-parent = <&gpio_intc>;
+			/* MAC_INTR on GPIOZ_15 */
 			interrupts = <29 IRQ_TYPE_LEVEL_LOW>;
 		};
 	};

arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts

@@ -174,8 +174,10 @@ mdio {
 		#size-cells = <0>;
 
 		eth_phy0: ethernet-phy@0 {
+			/* Realtek RTL8211F (0x001cc916) */
 			reg = <0>;
 			interrupt-parent = <&gpio_intc>;
+			/* MAC_INTR on GPIOZ_15 */
 			interrupts = <29 IRQ_TYPE_LEVEL_LOW>;
 			eee-broken-1000t;
 		};

arch/arm64/boot/dts/amlogic/meson-gxbb-p200.dts

@@ -118,6 +118,7 @@ eth_phy0: ethernet-phy@3 {
 			/* Micrel KSZ9031 (0x00221620) */
 			reg = <3>;
 			interrupt-parent = <&gpio_intc>;
+			/* MAC_INTR on GPIOZ_15 */
 			interrupts = <29 IRQ_TYPE_LEVEL_LOW>;
 		};
 	};

arch/arm64/boot/dts/amlogic/meson-gxm-q200.dts

@@ -111,6 +111,7 @@ external_phy: ethernet-phy@0 {
 		reg = <0>;
 		max-speed = <1000>;
 		interrupt-parent = <&gpio_intc>;
+		/* MAC_INTR on GPIOH_3 */
 		interrupts = <29 IRQ_TYPE_LEVEL_LOW>;
 	};
 };