irqchip/s3c24xx: Mark init_eint as __maybe_unused

The init_eint array in the s3c24xx irqchip driver is used by
every individual chip variant, but Kconfig allows building
the driver when they are all disabled, and that leads to
a harmless compile-time warning:

drivers/irqchip/irq-s3c24xx.c:608:28: error: 'init_eint' defined but not used [-Werror=unused-variable]

This marks the array as __maybe_unused to avoid the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1453737499-1960073-1-git-send-email-arnd@arndb.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>