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/include/asm-powerpc/io.h b/include/asm-powerpc/io.h
index bf14ab4..e44cdfc 100644
--- a/include/asm-powerpc/io.h
+++ b/include/asm-powerpc/io.h
@@ -522,7 +522,7 @@
 #else
 /*
  * Enforce synchronisation of stores vs. spin_unlock
- * (this does it explicitely, though our implementation of spin_unlock
+ * (this does it explicitly, though our implementation of spin_unlock
  * does it implicitely too)
  */
 static inline void mmiowb(void)