Pull s390 fixes from Heiko Carstens:

 - Convert current_stack_pointer to a register alias like it is assumed
   if ARCH_HAS_CURRENT_STACK_POINTER is selected. The existing
   implementation as a function breaks CONFIG_HARDENED_USERCOPY
   sanity-checks

 - Get rid of -Warray-bounds warning within kexec code

 - Add minimal IBM z16 support by reporting a proper elf platform, and
   adding compile options

 - Update defconfigs

* tag 's390-5.18-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: enable CONFIG_HARDENED_USERCOPY in debug_defconfig
  s390: current_stack_pointer shouldn't be a function
  s390: update defconfigs
  s390/kexec: silence -Warray-bounds warning
  s390: allow to compile with z16 optimizations
  s390: add z16 elf platform