ARM: ux500: select the DB8540 pin controller

The pin controller is an inherent part of the SoC, without
it the system will not boot, thus it needs to be selected
from Kconfig.
Acked-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

arch/arm/mach-ux500/Kconfig

@@ -18,6 +18,7 @@ config UX500_SOC_DB8500
 	select CPU_FREQ_TABLE if CPU_FREQ
 	select MFD_DB8500_PRCMU
 	select PINCTRL_DB8500
+	select PINCTRL_DB8540
 	select REGULATOR
 	select REGULATOR_DB8500_PRCMU