ARM: dts: exynos: Fix invalid node referenced by i2c20 alias in Peach Pit and Pi

After moving all nodes under "soc" node in commit 5d99cc59 ("ARM:
dts: exynos: Move Exynos5250 and Exynos5420 nodes under soc"), the i2c20
alias in Peach Pit and Peach Pi stopped pointing to proper node:

    arch/arm/boot/dts/exynos5420-peach-pit.dtb: Warning (alias_paths):
        /aliases:i2c20: aliases property is not a valid node (/spi@12d40000/cros-ec@0/i2c-tunnel)
    arch/arm/boot/dts/exynos5800-peach-pi.dtb: Warning (alias_paths):
        /aliases:i2c20: aliases property is not a valid node (/spi@12d40000/cros-ec@0/i2c-tunnel)

Fixes: 5d99cc59 ("ARM: dts: exynos: Move Exynos5250 and Exynos5420 nodes under soc")
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

arch/arm/boot/dts/exynos5420-peach-pit.dts

@@ -29,7 +29,7 @@ / {
 
 	aliases {
 		/* Assign 20 so we don't get confused w/ builtin ones */
-		i2c20 = "/spi@12d40000/cros-ec@0/i2c-tunnel";
+		i2c20 = &i2c_tunnel;
 	};
 
 	backlight: backlight {
@@ -970,7 +970,7 @@ controller-data {
 			samsung,spi-feedback-delay = <1>;
 		};
 
-		i2c-tunnel {
+		i2c_tunnel: i2c-tunnel {
 			compatible = "google,cros-ec-i2c-tunnel";
 			#address-cells = <1>;
 			#size-cells = <0>;

arch/arm/boot/dts/exynos5800-peach-pi.dts

@@ -27,7 +27,7 @@ / {
 
 	aliases {
 		/* Assign 20 so we don't get confused w/ builtin ones */
-		i2c20 = "/spi@12d40000/cros-ec@0/i2c-tunnel";
+		i2c20 = &i2c_tunnel;
 	};
 
 	backlight: backlight {
@@ -939,7 +939,7 @@ controller-data {
 			samsung,spi-feedback-delay = <1>;
 		};
 
-		i2c-tunnel {
+		i2c_tunnel: i2c-tunnel {
 			compatible = "google,cros-ec-i2c-tunnel";
 			#address-cells = <1>;
 			#size-cells = <0>;