MIPS: asm: irqflags: Add MIPS R6 related definitions

Add the MIPS R6 related definitions to the IRQ related macros

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
diff --git a/arch/mips/lib/mips-atomic.c b/arch/mips/lib/mips-atomic.c
index be777d9..272af8a 100644
--- a/arch/mips/lib/mips-atomic.c
+++ b/arch/mips/lib/mips-atomic.c
@@ -15,7 +15,7 @@
 #include <linux/export.h>
 #include <linux/stringify.h>
 
-#ifndef CONFIG_CPU_MIPSR2
+#if !defined(CONFIG_CPU_MIPSR2) && !defined(CONFIG_CPU_MIPSR6)
 
 /*
  * For cli() we have to insert nops to make sure that the new value