These are not Architecture specific in any way so move them out of
cpu-defs.h. tb-hash.h is an appropriate place as a leading user and
their strong relationship to TB hashing and caching.
Backports commit 41da4bd6420afd1209c408974920f63ff9c658e1 from qemu
This is one of very few things in exec-all with a genuine CPU
architecture dependency. Move these hashing helpers to a new
header to trim exec-all.h down to a near architecture-agnostic
header.
The defs are only used by cpu-exec and translate-all which are both
arch-obj's so the new tb-hash.h has no core code usage.
Backports commit e1b89321bafea9fb33d87852fc91fee579d17dfe from qemu