lapdm: Fix typo in the comment
diff --git a/src/gsm/lapdm.c b/src/gsm/lapdm.c
index 52290cb..19f78a1 100644
--- a/src/gsm/lapdm.c
+++ b/src/gsm/lapdm.c
@@ -1081,7 +1081,7 @@
 	else
 		le = &lc->lapdm_dcch;
 
-	/* G.2.1 No action schall be taken on frames containing an unallocated
+	/* G.2.1 No action shall be taken on frames containing an unallocated
 	 * SAPI.
 	 */
 	dl = datalink_for_sapi(le, sapi);