irqchip: Define EXYNOS_IRQ_COMBINER

This patch is written to clean up dependency of ARCH_EXYNOS
Not all exynos device have IRQ_COMBINER, especially aarch64 EXYNOS
but it is built for all exynos devices.
Thus add the config for EXYNOS_IRQ_COMBINER
remove direct dependency between ARCH_EXYNOS and exynos-combiner.c
and only selected on the aarch32 devices

Signed-off-by: Hyunki Koo <hyunki00.koo@samsung.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20191224211108.7128-1-hyunki00.koo@gmail.com
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 6c9262c..4b1c511 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -9,7 +9,7 @@
 obj-$(CONFIG_ARCH_BCM2835)		+= irq-bcm2836.o
 obj-$(CONFIG_DAVINCI_AINTC)		+= irq-davinci-aintc.o
 obj-$(CONFIG_DAVINCI_CP_INTC)		+= irq-davinci-cp-intc.o
-obj-$(CONFIG_ARCH_EXYNOS)		+= exynos-combiner.o
+obj-$(CONFIG_EXYNOS_IRQ_COMBINER)	+= exynos-combiner.o
 obj-$(CONFIG_FARADAY_FTINTC010)		+= irq-ftintc010.o
 obj-$(CONFIG_ARCH_HIP04)		+= irq-hip04.o
 obj-$(CONFIG_ARCH_LPC32XX)		+= irq-lpc32xx.o