mips: Implement arch_irqs_disabled()

Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200826101653.GE1362448@hirez.programming.kicks-ass.net

arch/mips/include/asm/irqflags.h

@@ -137,6 +137,11 @@ static inline int arch_irqs_disabled_flags(unsigned long flags)
 	return !(flags & 1);
 }
 
+static inline int arch_irqs_disabled(void)
+{
+	return arch_irqs_disabled_flags(arch_local_save_flags());
+}
+
 #endif /* #ifndef __ASSEMBLY__ */
 
 /*