pci and string functions changes on features depend on changes from the
fixes branch.

* fixes:
  s390: add Alexander Gordeev as reviewer
  s390: fix strrchr() implementation
  vfio-ccw: step down as maintainer
  KVM: s390: remove myself as reviewer
  s390/pci: fix zpci_zdev_put() on reserve
  bpf, s390: Fix potential memory leak about jit_data
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>