pinctrl: Define of_pinctrl_get() dummy for !PINCTRL

Currently, the of_pinctrl_get() dummy is only defined for !OF, which can
still cause build failures on configurations with OF enabled but PINCTRL
disabled. Make sure to define the dummy if either OF or PINCTRL are not
enabled.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20200330095801.2421589-1-thierry.reding@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

include/linux/pinctrl/pinctrl.h

@@ -186,7 +186,7 @@ extern int pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
 				const char *pin_group, const unsigned **pins,
 				unsigned *num_pins);
 
-#ifdef CONFIG_OF
+#if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_PINCTRL)
 extern struct pinctrl_dev *of_pinctrl_get(struct device_node *np);
 #else
 static inline