eth: fbnic: Add initial messaging to notify FW of our presence

After the driver loads we need to get some initial capabilities from the
firmware to determine what the device is capable of and what functionality
needs to be enabled. Specifically we receive information about the current
state of the link and if a BMC is present.

After that when we bring the interface up we will need the ability to take
ownership from the FW. To do that we will need to notify it that we are
taking control before we start configuring the traffic classifier and MAC.

Once we have ownership we need to notify the firmware that we are still
present and active. To do that we will send a regular heartbeat to the FW.
If the FW doesn't receive the heartbeat in a timely fashion it will retake
control of the RPC and MAC and assume that the host has gone offline.

Signed-off-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://patch.msgid.link/172079939458.1778861.8966209942099133957.stgit@ahduyck-xeon-server.home.arpa


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