irqchip: Remove unused include

The "irqchip.h" include here is not needed as the only thing in
irqchip.h is IRQCHIP_DECLARE which this file doesn't use. Drop
it.

Reported-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Link: http://lkml.kernel.org/r/531F7765.40207@codeaurora.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --cc drivers/irqchip/irqchip.c
Simple merge