ARM: dts: koelsch: Convert to named i2c-gpio bindings

Commits 7d29f509 ("dt-bindings: i2c: i2c-gpio: Add support for
named gpios") and 05c74778 ("i2c: gpio: Add support for named
gpios in DT") introduced named i2c-gpio DT bindings, and deprecated the
more error-prone unnamed variant.

Switch to the new bindings, and add the missing GPIO_OPEN_DRAIN I/O
flags, which were implicitly assumed before.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7791-koelsch.dts

@@ -312,9 +312,8 @@ gpioi2c1: i2c-9 {
 		#size-cells = <0>;
 		compatible = "i2c-gpio";
 		status = "disabled";
-		gpios = <&gpio7 16 GPIO_ACTIVE_HIGH /* sda */
-			 &gpio7 15 GPIO_ACTIVE_HIGH /* scl */
-			>;
+		sda-gpios = <&gpio7 16 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+		scl-gpios = <&gpio7 15 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 		i2c-gpio,delay-us = <5>;
 	};