gve: Add adminq command to report nic timestamp

gve: Add adminq command to report nic timestamp

Add an adminq command to read NIC's hardware clock. The driver
allocates dma memory and passes that dma memory address to the device.
The device then writes the clock to the given address.

Signed-off-by: Jeff Rogers <jefrogers@google.com>
Signed-off-by: John Fraker <jfraker@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
Link: https://patch.msgid.link/20250614000754.164827-3-hramamurthy@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>