pinctrl: s3c24xx: use correct header for chained_irq functions

chained_irq_enter and chained_irq_exit moved to a real header
under linux/pinctrl instead of asm/.

Update the pinctrl driver to use the correct header and fix the
build error.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>`
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

drivers/pinctrl/pinctrl-s3c24xx.c

@@ -19,12 +19,11 @@
 #include <linux/irqdomain.h>
 #include <linux/irq.h>
 #include <linux/of_irq.h>
+#include <linux/irqchip/chained_irq.h>
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/err.h>
 
-#include <asm/mach/irq.h>
-
 #include "pinctrl-samsung.h"
 
 #define NUM_EINT	24