hyperv: Add support for physically discontinuous receive buffer

This will allow us to use bigger receive buffer, and prevent allocation failure
due to fragmented memory.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>