kernel: backport MIPS changes introducing a separate IRQ stack

Prevents crashes when IRQs arrive when the current kernel stack context
already contains deeply nested function calls, e.g. when stacking lots
of network devices on top of each other

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/brcm63xx/patches-4.4/322-MIPS-BCM63XX-switch-to-IRQ_DOMAIN.patch

@@ -14,7 +14,7 @@ Signed-off-by: Jonas Gorski <jogo@openwrt.org>
 
 --- a/arch/mips/Kconfig
 +++ b/arch/mips/Kconfig
-@@ -206,6 +206,9 @@ config BCM63XX
+@@ -207,6 +207,9 @@ config BCM63XX
  	select SYNC_R4K
  	select DMA_NONCOHERENT
  	select IRQ_MIPS_CPU