hv_sock: Use consistent types for UUIDs

The rest of Hyper-V code is using new types for UUID handling.
Convert hv_sock as well.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>