Implement the following syscalls:
stat(2)
lstat(2)
fstat(2)
fstatat(2)
nstat
nfstat
nlstat

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>