gve: add support to read ring size ranges from the device

gve: add support to read ring size ranges from the device

Add support to read ring size change capability and the
min and max descriptor counts from the device and store it
in the driver. Also accommodate a special case where the
device does not provide minimum ring size depending on the
version of the device. In that case, rely on default values
for the minimums.

Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>