pinctrl: lochnagar: select GPIOLIB

In a rare randconfig build I came across one configuration that does
not enable CONFIG_GPIOLIB, which is needed by lochnagar:

ERROR: "devm_gpiochip_add_data" [drivers/pinctrl/cirrus/pinctrl-lochnagar.ko] undefined!
ERROR: "gpiochip_generic_free" [drivers/pinctrl/cirrus/pinctrl-lochnagar.ko] undefined!
ERROR: "gpiochip_generic_request" [drivers/pinctrl/cirrus/pinctrl-lochnagar.ko] undefined!
ERROR: "gpiochip_get_data" [drivers/pinctrl/cirrus/pinctrl-lochnagar.ko] undefined!

Add another 'select' like all other pinctrl drivers have.

Fixes: 0548448b ("pinctrl: lochnagar: Add support for the Cirrus Logic Lochnagar")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20191218163701.171914-1-arnd@arndb.deAcked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/cirrus/Kconfig

@@ -2,6 +2,7 @@
 config PINCTRL_LOCHNAGAR
 	tristate "Cirrus Logic Lochnagar pinctrl driver"
 	depends on MFD_LOCHNAGAR
+	select GPIOLIB
 	select PINMUX
 	select PINCONF
 	select GENERIC_PINCONF