ARM: mc146818rtc: remove unnecessary include of mach/irqs.h

The include of mach/irqs.h isn't needed, so remove it. Compiled CMOS rtc
driver. Add a check to make sure nothing depends on RTC_IRQ.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>

arch/arm/include/asm/mc146818rtc.h

@@ -5,7 +5,9 @@
 #define _ASM_MC146818RTC_H
 
 #include <linux/io.h>
-#include <mach/irqs.h>
+#include <linux/kernel.h>
+
+#define RTC_IRQ BUILD_BUG_ON(1)
 
 #ifndef RTC_PORT
 #define RTC_PORT(x)	(0x70 + (x))