ARM: 7189/1: OMAP3: Fix build break in cpuidle34xx.c because of irq function

Fix the below build break by including common.h

arch/arm/mach-omap2/cpuidle34xx.c: In function 'omap3_enter_idle':
arch/arm/mach-omap2/cpuidle34xx.c:117: error: implicit declaration of function 'omap_irq_pending'
make[1]: *** [arch/arm/mach-omap2/cpuidle34xx.o] Error 1
make: *** [arch/arm/mach-omap2] Error 2

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>