VSOCK: do not try to manually request VMCI

The module loader should resolve the dependencies automatically; there
is no need to explicitly load VMCI, especially if we want to have
several possible transports.

Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
VSOCK: rearrange code to get rid of forward declarations

There is no point in defining socket operations ahead of time...

Acked-by: Andy King <acking@vmware.com>
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>