irqchip/omap-intc: Remove duplicate setup for IRQ chip type handler

Some OMAP interrupt controllers use generic level detection, so
handle_level_irq() is used as the chip type handler.
Allocated IRQ chip type handler doesn't need to set it again because
irq_alloc_domain_generic_chips() has already registered it.

Tested with BeagleBoneBlack Rev C.

Signed-off-by: Milo Kim <milo.kim@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-omap@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1450687994-12580-1-git-send-email-milo.kim@ti.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>