qcacmn: qdf: Replace fallthrough comment with attribute

-Wimplicit-fallthrough is being enabled by default. Some compilers
such as clang require the attribute instead of just a fallthrough comment.

Change-Id: Ib87c694224af8e1331d813b64e02dc4ec0c176d8
CRs-Fixed: 3218237

qdf/src/qdf_parse.c

@@ -54,7 +54,7 @@ static QDF_STATUS qdf_ini_read_values(char **main_cursor,
 			case '\n':
 				*cursor = '\0';
 				cursor++;
-				/* fall through */
+				fallthrough;
 			case '\0':
 				eol = true;
 				break;
@@ -79,7 +79,7 @@ static QDF_STATUS qdf_ini_read_values(char **main_cursor,
 				 */
 				comment = true;
 				*cursor = '\0';
-				/* fall through */
+				fallthrough;
 			default:
 				cursor++;
 				break;