Pull Xtensa updates from Max Filippov:

 - fix kconfig unmet dependency warning for HAVE_FUTEX_CMPXCHG

 - add fairness to handling IRQs of the same priority

 - fix pointer usage before NULL check in ISS console driver

 - build system cleanups

* tag 'xtensa-20210902' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: move core-y in arch/xtensa/Makefile to arch/xtensa/Kbuild
  xtensa: build platform directories unconditionally
  xtensa: do not build variants directory
  xtensa: remove unneeded exports
  xtensa: ISS: don't use string pointer before NULL check
  xtensa: add fairness to IRQ handling
  xtensa: fix kconfig unmet dependency warning for HAVE_FUTEX_CMPXCHG