ARM: dts: exynos: Align MHL GPIO pin configuration with dtschema on Galaxy I9100

Align the name of mag-mhl-gpio node to avoid dtschema confusion and
dtbs_check warning:

  arch/arm/boot/dts/exynos4210-i9100.dt.yaml: pinctrl@11000000: mag-mhl-gpio:
    {'samsung,pins': ['gpd0-2'], 'samsung,pin-function': [[3]], 'samsung,pin-pud': [[0]]} is not of type 'array'
    From schema: dtschema/schemas/gpio/gpio-consumer.yaml
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200830135200.24304-22-krzk@kernel.org

arch/arm/boot/dts/exynos4210-i9100.dts

@@ -681,7 +681,7 @@ otg_gp: otg-gp {
 		samsung,pin-val = <0>;
 	};
 
-	mag_mhl_gpio: mag-mhl-gpio {
+	mag_mhl_gpio: mag-mhl {
 		samsung,pins = "gpd0-2";
 		samsung,pin-function = <EXYNOS_PIN_FUNC_3>;
 		samsung,pin-pud = <EXYNOS_PIN_PULL_NONE>;