gve: Add adminq extended command

The adminq command is limited to 64 bytes per entry and it's 56 bytes
for the command itself at maximum. To support larger commands, we need
to dma_alloc a separate memory to put the command in that memory and
send the dma memory address instead of the actual command.

Introduce an extended adminq command to wrap the real command with the
inner opcode and the allocated dma memory address specified. Once the
device receives it, it can get the real command from the given dma
memory address. As designed with the device, all the extended commands
will use inner opcode larger than 0xFF.

Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240625001232.1476315-3-ziweixiao@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>