I've accidentally stumbled upon the IS_ENABLED(EXPOLINE_*) lines, which
obviously always evaluate to false. Fix this.

Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Signed-off-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>