pinctrl: s3c64xx: Fix build error caused by undefined chained_irq_enter

Commit de88cbb7 moved definitions of chained_irq_enter and
chained_irq_exit to a generic header, which must be now included instead
of the legacy arch-specific one.

This patch fixes build error caused by including the legacy header
leading to undefined chained_irq_enter and chained_irq_exit symbols.
Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-s3c64xx.c

@@ -22,11 +22,10 @@
 #include <linux/irq.h>
 #include <linux/of_irq.h>
 #include <linux/io.h>
+#include <linux/irqchip/chained_irq.h>
 #include <linux/slab.h>
 #include <linux/err.h>
 
-#include <asm/mach/irq.h>
-
 #include "pinctrl-samsung.h"
 
 #define NUM_EINT0		28