sh: gpio: Include asm-generic/gpio.h for non-gpiolib stubs.

Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/gpio.h

@@ -99,9 +99,7 @@ int gpio_direction_input(unsigned gpio);
 int gpio_direction_output(unsigned gpio, int value);
 int gpio_get_value(unsigned gpio);
 void gpio_set_value(unsigned gpio, int value);
-static inline int gpio_export(unsigned gpio, bool direction_may_change)
-{
-	return 0;
-}
+
+#include <asm-generic/gpio.h>
 
 #endif /* __ASM_SH_GPIO_H */