cxgb4: Fix the condition to check if the card is T5

Use 'chip_ver' rather than 'chip' to check if the card
is T5.

Fixes: e8d45292

 ("cxgb4: clean up init_one")
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>