vxlan: Don't set s_addr in vxlan_create_sock

In the case of AF_INET s_addr was set to INADDR_ANY (0) which which both
symmetric with the AF_INET6 case, where s_addr is not set, and unnecessary
as udp_conf is zeroed out earlier in the same function.

I suspect this change does not have any run-time effect due to compiler
optimisations. But it does make the code a little easier on the/my eyes.

Cc: Tom Herbert <therbert@google.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>