sh: asm/gpio.h needs linux/kernel.h for might_sleep()/WARN_ON().

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

arch/sh/include/asm/gpio.h

@@ -12,6 +12,7 @@
 #ifndef __ASM_SH_GPIO_H
 #define __ASM_SH_GPIO_H
 
+#include <linux/kernel.h>
 #include <linux/errno.h>
 
 #if defined(CONFIG_CPU_SH3)