devtools: fix comment detection in forbidden token check

After a comment section was detected, passing to a new hunk was not seen
as ending the section and all subsequent hunks were ignored.

Fixes: 7413e7f2ae ("devtools: alert on new calls to exit from libs")
Cc: stable@dpdk.org

Reported-by: Thomas Monjalon <thomas@monjalon.net>
Signed-off-by: David Marchand <david.marchand@redhat.com>

devtools/check-forbidden-tokens.awk

@@ -20,6 +20,9 @@ BEGIN {
 # state machine assumes the comments structure is enforced by
 # checkpatches.pl
 (in_file) {
+	if ($0 ~ "^@@") {
+		in_comment = 0
+	}
 	# comment start
 	if (index($0,comment_start) > 0) {
 		in_comment = 1