irqchip/omap-intc: Fix missing <linux/irqchip/irq-omap-intc.h> include

irqchip/omap-intc: Fix missing <linux/irqchip/irq-omap-intc.h> include

Fix the missing include of <linux/irqchip/irq-omap-intc.h> which
declares all the missing functions from the following warnings:

drivers/irqchip/irq-omap-intc.c:84:6: warning: symbol 'omap_intc_save_context' was not declared. Should it be static?
drivers/irqchip/irq-omap-intc.c:105:6: warning: symbol 'omap_intc_restore_context' was not declared. Should it be static?
drivers/irqchip/irq-omap-intc.c:124:6: warning: symbol 'omap3_intc_prepare_idle' was not declared. Should it be static?
drivers/irqchip/irq-omap-intc.c:134:6: warning: symbol 'omap3_intc_resume_idle' was not declared. Should it be static?
drivers/irqchip/irq-omap-intc.c:173:5: warning: symbol 'omap_irq_pending' was not declared. Should it be static?
drivers/irqchip/irq-omap-intc.c:183:6: warning: symbol 'omap3_intc_suspend' was not declared. Should it be static?
drivers/irqchip/irq-omap-intc.c:365:13: warning: symbol 'omap3_init_irq' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Link: https://lkml.kernel.org/r/1465407872-10299-1-git-send-email-ben.dooks@codethink.co.uk
Signed-off-by: Jason Cooper <jason@lakedaemon.net>