ARM: GIC: Make MULTI_IRQ_HANDLER mandatory

Now that MULTI_IRQ_HANDLER is selected by all the in-tree
GIC users, make it mandatory and remove the unused macros.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig
index a3beda1..a11cee5 100644
--- a/arch/arm/common/Kconfig
+++ b/arch/arm/common/Kconfig
@@ -1,5 +1,6 @@
 config ARM_GIC
 	select IRQ_DOMAIN
+	select MULTI_IRQ_HANDLER
 	bool
 
 config GIC_NON_BANKED