fio: fix s390 timing for older machines/binutils

Older gcc/binutils or one with very low default march will refuse to use stckf.
On top of that machines older than a z196 don not even have the store clock
fast facility.

To fix all of those issues, check for the facilities in configure step and make
the usage of stckf and a matching march dependent to it.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@fb.com>