[S390] stack dump: fix indentation in output

The first line of a stack dump has a wrong (no) indentation.
Just fix this after more than 10 years.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
1 file changed