irq: Export handle_fasteoi_irq

Export handle_fasteoi_irq to be able to use it in e.g. the Zynq gpio driver
since commit 6dd8595083 ("gpio: zynq: Fix IRQ handlers").

This fixes the following link issue:

  ERROR: "handle_fasteoi_irq" [drivers/gpio/gpio-zynq.ko] undefined!

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Vincent Stehle <vincent.stehle@laposte.net>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: http://lkml.kernel.org/r/1408663880-29179-1-git-send-email-vincent.stehle@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/chip.c

@@ -517,6 +517,7 @@ out:
 		chip->irq_eoi(&desc->irq_data);
 	raw_spin_unlock(&desc->lock);
 }
+EXPORT_SYMBOL_GPL(handle_fasteoi_irq);
 
 /**
  *	handle_edge_irq - edge type IRQ handler