gve: Unify duplicate GQ min pkt desc size constants

The two constants accomplish the same thing.

Signed-off-by: Shailend Chand <shailend@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230407184830.309398-1-shailend@google.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>