x86/mm: Initialize text poking earlier

x86/mm: Initialize text poking earlier

commit 5b93a83649c7cba3a15eb7e8959b250841acb1b1 upstream.

Move poking_init() up a bunch; specifically move it right after
mm_init() which is right before ftrace_init().

This will allow simplifying ftrace text poking which currently has
a bunch of exceptions for early boot.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221025201057.881703081@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>