The introduction of stricter mmap_lock checking in translate-all broke
the BSD user build. The working mmap_lock functions were hidden behind
CONFIG_USE_NPTL which is never defined. This patch brings them inline
with linux-user.

Despite the disapearence of the comment "We aren't threadsafe to start
with..." this doesn't make bsd-user so. It will still need the rest of
the fixes that have been done in linux-user ported over.
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>