metag: Turn irq_ctx_* macros into static inlines

The irq_ctx_init()/irq_ctx_exit() functions are only used for 4KiB
stacks, otherwise they are implemented as an empty macro. To prevent
future bit rottage due to the cpu argument not being type checked,
convert the macros to empty static inline functions.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org

arch/metag/include/asm/irq.h

@@ -6,8 +6,12 @@ extern void irq_ctx_init(int cpu);
 extern void irq_ctx_exit(int cpu);
 # define __ARCH_HAS_DO_SOFTIRQ
 #else
-# define irq_ctx_init(cpu) do { } while (0)
-# define irq_ctx_exit(cpu) do { } while (0)
+static inline void irq_ctx_init(int cpu)
+{
+}
+static inline void irq_ctx_exit(int cpu)
+{
+}
 #endif
 
 void tbi_startup_interrupt(int);