ARM: 7188/1: OMAP2PLUS: Fix build error: 'omap2/omap3_intc_handle_irq' undeclared.

Fix the build break by adding the necessary irq functions to
common header.

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