arm64: dts: exynos: Fix silent hang after boot on Espresso

[ Upstream commit b072714b ]

Once regulators are disabled after kernel boot, on Espresso board silent
hang observed because of LDO7 being disabled.  LDO7 actually provide
power to CPU cores and non-cpu blocks circuitries.  Keep this regulator
always-on to fix this hang.

Fixes: 9589f772 ("arm64: dts: Add S2MPS15 PMIC node on exynos7-espresso")
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/arm64/boot/dts/exynos/exynos7-espresso.dts

@@ -152,6 +152,7 @@ ldo7_reg: LDO7 {
 				regulator-min-microvolt = <700000>;
 				regulator-max-microvolt = <1150000>;
 				regulator-enable-ramp-delay = <125>;
+				regulator-always-on;
 			};
 
 			ldo8_reg: LDO8 {