atlantic: Fix statistics logic for production hardware

B0 is the main and widespread device revision of atlantic2 HW. In the
current state, driver will incorrectly fetch the statistics for this
revision.

Fixes: 5cfd54d7

 ("net: atlantic: minimal A2 fw_ops")
Signed-off-by: Dmitry Bogdanov <dbezrukov@marvell.com>
Signed-off-by: Sudarsana Reddy Kalluru <skalluru@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>