powerpc/kcsan: Prevent recursive instrumentation with IRQ save/restores

powerpc/kcsan: Prevent recursive instrumentation with IRQ save/restores

Instrumented memory accesses provided by KCSAN will access core-local
memories (which will save and restore IRQs) as well as restoring IRQs
directly. Avoid recursive instrumentation by applying __no_kcsan
annotation to IRQ restore routines.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
[mpe: Resolve merge conflict with IRQ replay recursion changes]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230206021801.105268-5-rmclure@linux.ibm.com