nios2: Do not include linux/irqdomain.h from asm/irq.h

Including linux/irqdomain.h from asm/irq.h is going to break
as soon as linux/irqdomain.h will include linux/irq.h, so
let's fix this. Code relying on linux/irqomain.h should include
it directly.
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/nios2/include/asm/irq.h

@@ -10,6 +10,5 @@
 #define NIOS2_CPU_NR_IRQS	32
 
 #include <asm-generic/irq.h>
-#include <linux/irqdomain.h>
 
 #endif

arch/nios2/kernel/irq.c

@@ -11,6 +11,7 @@
 
 #include <linux/init.h>
 #include <linux/interrupt.h>
+#include <linux/irqdomain.h>
 #include <linux/of.h>
 
 static u32 ienable;