MIPS: 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/mips/include/asm/irq.h

@@ -11,7 +11,6 @@
 
 #include <linux/linkage.h>
 #include <linux/smp.h>
-#include <linux/irqdomain.h>
 
 #include <asm/mipsmtregs.h>