octeontx2-af: NPC: Clear Unicast rule on nixlf detach

The AF driver assigns reserved MCAM entries (for unicast, broadcast,
etc.) based on the NIXLF number. When a NIXLF is detached, these entries
are disabled.

For example,

         PF           NIXLF
        --------------------
         PF0             0
         SDP-VF0         1

If the user unbinds both PF0 and SDP-VF0 interfaces and then binds them in
reverse order

         PF            NIXLF
        ---------------------
         SDP-VF0         0
         PF0             1

In this scenario, the PF0 unicast entry is getting corrupted because
the MCAM entry contains stale data (SDP-VF0 ucast data)

This patch resolves the issue by clearing the unicast MCAM entry during
NIXLF detach

Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>