ARM: ux500: Fix unmet direct dependency

A recent change to a Kconfig configuration saw MACH_U8500
remove TPS6105X selection. In doing so Kconfig stopped
selecting REGULATORS, which is still required. This patch
sees UX500_SOC_DB8500 explicitly select it instead.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/arch/arm/mach-ux500/Kconfig b/arch/arm/mach-ux500/Kconfig
index 880d02e..ef7099e 100644
--- a/arch/arm/mach-ux500/Kconfig
+++ b/arch/arm/mach-ux500/Kconfig
@@ -17,6 +17,7 @@
 config UX500_SOC_DB8500
 	bool
 	select MFD_DB8500_PRCMU
+	select REGULATOR
 	select REGULATOR_DB8500_PRCMU
 	select CPU_FREQ_TABLE if CPU_FREQ