ARM: shmobile: r8a7791: remove deprecated #gpio-range-cells from dtsi

Commit a1bc260b ("gpio: clean up gpio-ranges documentation")
declares the above property deprecated. That was more than 2 years ago.
Remove it, so it doesn't get copied around needlessly.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7791.dtsi

@@ -509,7 +509,6 @@ i2c8: i2c@e6510000 {
 	pfc: pfc@e6060000 {
 		compatible = "renesas,pfc-r8a7791";
 		reg = <0 0xe6060000 0 0x250>;
-		#gpio-range-cells = <3>;
 	};
 
 	mmcif0: mmc@ee200000 {