Our bsd_to_linux_sockaddr() and linux_to_bsd_sockaddr() functions
alter the userspace sockaddr to convert the format between linux and BSD versions.
That's the minimum 3 of copyin/copyout operations for one syscall.
Also some syscall uses linux_sa_put() and linux_getsockaddr() when load
sockaddr to userspace or from userspace accordingly.
To avoid this, chaos especially converting sockaddr in the userspace,
rewrite these 4 functions to convert sockaddr only in kernel and leave
only 2 of this functions.
Also in order to reduce duplication between MD parts of the Linuxulator move
struct sockaddr conversion functions that are MI out into linux_common module.