spelling fixes: arch/m32r/

Spelling fixes in arch/m32r/.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
diff --git a/arch/m32r/kernel/irq.c b/arch/m32r/kernel/irq.c
index f8d8650..d0c5b0b 100644
--- a/arch/m32r/kernel/irq.c
+++ b/arch/m32r/kernel/irq.c
@@ -71,7 +71,7 @@
 }
 
 /*
- * do_IRQ handles all normal device IRQ's (the special
+ * do_IRQ handles all normal device IRQs (the special
  * SMP cross-CPU interrupts have their own specific
  * handlers).
  */