cxgb4: use CLIP with LIP6 on T6 for TCAM filters

On T6, LIP compression is always enabled for IPv6 and uncompressed
IPv6 for LIP is not supported. So, for IPv6 TCAM filters on T6,
add LIP6 to CLIP on filter creation, and release the same on filter
deletion.

Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>