Spelling fix: explicitly

From: Jean Delvare <khali@linux-fr.org>

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 2250f9e..b0e5deb 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -491,7 +491,7 @@
 
 			/* Legacy flags are left to default at this point,
 			 * one can then use irq_create_mapping() to
-			 * explicitely change them
+			 * explicitly change them
 			 */
 			ops->map(host, i, i);
 		}