eth: fbnic: add MAC address TCAM to debugfs

eth: fbnic: add MAC address TCAM to debugfs

Add read only access to the 32-entry MAC address TCAM via debugfs.
BMC filtering shares the same table so this is quite useful
to access during debug. See next commit for an example output.

Signed-off-by: Alexander Duyck <alexanderduyck@meta.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250204010038.1404268-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>