ipw2x00: comment typo fix encryptiong to encryption

The below patch fixes a typo.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/net/wireless/ipw2x00/libipw_tx.c b/drivers/net/wireless/ipw2x00/libipw_tx.c
index 01c88a7..e8c0398 100644
--- a/drivers/net/wireless/ipw2x00/libipw_tx.c
+++ b/drivers/net/wireless/ipw2x00/libipw_tx.c
@@ -395,7 +395,7 @@
 		    (CFG_LIBIPW_COMPUTE_FCS | CFG_LIBIPW_RESERVE_FCS))
 			bytes_per_frag -= LIBIPW_FCS_LEN;
 
-		/* Each fragment may need to have room for encryptiong
+		/* Each fragment may need to have room for encryption
 		 * pre/postfix */
 		if (host_encrypt)
 			bytes_per_frag -= crypt->ops->extra_mpdu_prefix_len +