gve: Fix warnings reported for DQO patchset

https://patchwork.kernel.org/project/netdevbpf/list/?series=506637&state=*



- Remove unused variable
- Use correct integer type for string formatting.
- Remove `inline` in C files

Fixes: 9c1a59a2 ("gve: DQO: Add ring allocation and initialization")
Fixes: a57e5de4 ("gve: DQO: Add TX path")
Signed-off-by: Bailey Forrest <bcf@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>