net/mlx4_core: Fixes missing capability bit in flags2 capability dump

The cited commit introduced the following new enum value in file
include/linux/mlx4/device.h:

    QUERY_DEV_CAP_DIAG_RPRT_PER_PORT

However, it failed to introduce a corresponding entry in function
dump_dev_cap_flags2() for outputting a line in the message log
when this capability bit is set.

The change here fixes that omission.

Fixes: c7c122ed ("net/mlx4: Add diagnostic counters capability bit")
Reported-by: Mukesh Kacker <mukesh.kacker@oracle.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>