pinctrl: single: Use generic pinmux helpers for managing functions

We can now drop the driver specific code for managing functions.

Signed-off-by: Tony Lindgren <tony@atomide.com>
[Replaces GENERIC_PINMUX with GENERIC_PINMUX_FUNCTIONS]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index d2fbcea..e806f96 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -167,7 +167,7 @@
 	tristate "One-register-per-pin type device tree based pinctrl driver"
 	depends on OF
 	select GENERIC_PINCTRL_GROUPS
-	select PINMUX
+	select GENERIC_PINMUX_FUNCTIONS
 	select GENERIC_PINCONF
 	help
 	  This selects the device tree based generic pinctrl driver.