Fix dead URLs to ftp.kernel.org

URLs to ftp.kernel.org are still exist though the service is closed [0].
This commit fixes the URLs to use www.kernel.org instead.

[0] https://www.kernel.org/shutting-down-ftp-services.html

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/scripts/package/builddeb b/scripts/package/builddeb
index 3c575cd0..676fc10 100755
--- a/scripts/package/builddeb
+++ b/scripts/package/builddeb
@@ -262,8 +262,8 @@
 cat <<EOF > debian/copyright
 This is a packacked upstream version of the Linux kernel.
 
-The sources may be found at most Linux ftp sites, including:
-ftp://ftp.kernel.org/pub/linux/kernel
+The sources may be found at most Linux archive sites, including:
+https://www.kernel.org/pub/linux/kernel
 
 Copyright: 1991 - 2015 Linus Torvalds and others.