arch: Use asm-generic/socket.h when possible

Many architectures maintain an arch specific copy of the
file even though there are no differences with the asm-generic
one. Allow these architectures to use the generic one instead.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Cc: chris@zankel.net
Cc: fenghua.yu@intel.com
Cc: tglx@linutronix.de
Cc: schwidefsky@de.ibm.com
Cc: linux-ia64@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linux-s390@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>