eth: fbnic: Add support to write TCE TCAM entries

eth: fbnic: Add support to write TCE TCAM entries

Add support to redirect host-to-BMC traffic by writing MACDA entries
from the RPC (RX Parser and Classifier) to TCE-TCAM. The TCE TCAM is a
small L2 destination TCAM which is placed at the end of the TX path (TCE).

Unlike other NICs, where BMC diversion is typically handled by firmware,
for fbnic, firmware does not touch anything related to the host; hence,
the host uses TCE TCAM to divert BMC traffic.

Currently, we lack metadata to track where addresses have been written
in the TCAM, except for the last entry written. To address this issue,
we start at the opposite end of the table in each pass, so that adding
or deleting entries does not affect the availability of all entries,
assuming there is no significant reordering of entries.

Signed-off-by: Mohsin Bashir <mohsin.bashr@gmail.com>
Link: https://patch.msgid.link/20241104031300.1330657-1-mohsin.bashr@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>