[MIPS] IP32: Fix build by conversion to irq_cpu.c.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index f943736..f921235 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -410,6 +410,7 @@
 	select BOOT_ELF32
 	select DMA_NONCOHERENT
 	select HW_HAS_PCI
+	select IRQ_CPU
 	select R5000_CPU_SCACHE
 	select RM7000_CPU_SCACHE
 	select SYS_HAS_CPU_R5000