Input: ads7846 - drop unneeded asm/irq.h include

This is essentially a revert of:

	3ac8bf07 ("[PATCH] ads7846: sparc32 warning fix")

By now enable_irq() and disable_irq() are properly defined in
linux/interrupt.h and we do not need to pull in architecture-specific
bits.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/ads7846.c

@@ -32,7 +32,6 @@
 #include <linux/spi/ads7846.h>
 #include <linux/regulator/consumer.h>
 #include <linux/module.h>
-#include <asm/irq.h>
 #include <asm/unaligned.h>
 
 /*