bsd-user: common routine do_freebsd_sysctl_oid for all sysctl variants

bsd-user: common routine do_freebsd_sysctl_oid for all sysctl variants

do_freebsd_sysctl_oid filters out some of the binary and special sysctls
where host != target. None of the sysctls that have to be translated from
host to target are handled here.

Signed-off-by: Juergen Lock <nox@jelal.kn-bremen.de>
Co-Authored-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Stacey Son <sson@FreeBSD.org>
Co-Authored-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>