Pull more s390 updates from Heiko Carstens:
"This is mainly to decouple udelay() and arch_cpu_idle() and simplify
both of them.
Summary:
- Always initialize kernel stack backchain when entering the kernel,
so that unwinding works properly.
- Fix stack unwinder test case to avoid rare interrupt stack
corruption.
- Simplify udelay() and just let it busy loop instead of implementing
a complex logic.
- arch_cpu_idle() cleanup.
- Some other minor improvements"
* tag 's390-5.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/zcrypt: convert comma to semicolon
s390/idle: allow arch_cpu_idle() to be kprobed
s390/idle: remove raw_local_irq_save()/restore() from arch_cpu_idle()
s390/idle: merge enabled_wait() and arch_cpu_idle()
s390/delay: remove udelay_simple()
s390/irq: select HAVE_IRQ_EXIT_ON_IRQ_STACK
s390/delay: simplify udelay
s390/test_unwind: use timer instead of udelay
s390/test_unwind: fix CALL_ON_STACK tests
s390: make calls to TRACE_IRQS_OFF/TRACE_IRQS_ON balanced
s390: always clear kernel stack backchain before calling functions
a087241716