pinctrl/amd: Fix build dependency on pinmux code

The commit 79d2c8bede2c93f943 ("pinctrl/amd: save pin registers over
suspend/resume") caused the following compilation errors:

drivers/pinctrl/pinctrl-amd.c: In function ‘amd_gpio_should_save’:
drivers/pinctrl/pinctrl-amd.c:741:8: error: ‘const struct pin_desc’ has no member named ‘mux_owner’
if (pd->mux_owner || pd->gpio_owner ||
^
drivers/pinctrl/pinctrl-amd.c:741:25: error: ‘const struct pin_desc’ has no member named ‘gpio_owner’
if (pd->mux_owner || pd->gpio_owner ||

We need to enable CONFIG_PINMUX for this driver as well.

Cc: [e-mail]
Fixes: 79d2c8bede2c93f943 ("pinctrl/amd: save pin registers over suspend/resume")
Signed-off-by: Petr Mladek <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/Kconfig

···
 	tristate "AMD GPIO pin control"
 	depends on GPIOLIB
 	select GPIOLIB_IRQCHIP
+	select PINMUX
 	select PINCONF
 	select GENERIC_PINCONF
 	help