ARM: tegra: nexus7: Correct 3v3 regulator GPIO of PM269 variant

The 3v3 regulator GPIO is GP6 and not GP7, which is the DDR regulator.
Both regulators are always-on, nevertheless the DT model needs to be
corrected, fix it.
Reported-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra30-asus-nexus7-grouper-ti-pmic.dtsi

@@ -144,7 +144,7 @@ vdd_core: core-regulator@60 {
 	};
 
 	vdd_3v3_sys: regulator@1 {
-		gpio = <&pmic 7 GPIO_ACTIVE_HIGH>;
+		gpio = <&pmic 6 GPIO_ACTIVE_HIGH>;
 		enable-active-high;
 	};