powerpc/mm/hash: Abstract context id allocation for KVM

KVM wants to be able to allocate an MMU context id, which it does
currently by calling __init_new_context().

We're about to rework that code, so provide a wrapper for KVM so it
can not worry about the details.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
3 files changed