arm: mach-omap2: omap_l3_smx: fix irq handler setup

The handler function may be called from the point it is registered.
Since the handler inspects IRQ numbers, we must set them up before
registration.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>