bsd-user: Add getdents and fcntl related system calls

Add glue to call the following syscalls to the freebsd_syscall:

freebsd11_getdents
getdirentries
freebsd11_getdirentries
fcntl

Signed-off-by: Warner Losh <imp@bsdimp.com>
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>