[S390] ftrace: function tracer backend for s390

This implements just the basic function tracer (_mcount) backend for s390.
The dynamic variant will come later.

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