net/mlx4_core: Deprecate error message at ConnectX-2 cards startup to debug

ConnectX2 HCAs have max_mtu=4k and max_vl=8 vls. However, if you specify
a 4K mtu, the max_vl supported for 4K is 4 vls. The driver at startup
attempts to set a 4K mtu using the max_vl value obtained from QUERY_PORT.

Since the max_vl value is 8 vls (which is supported up to 2K mtu size),
the first attempt to set the mtl/vl port value will fail, generating
the following error message in the log:

  mlx4_core 0000:06:00.0: command 0xc failed: fw status = 0x40

The driver then tries again, using mtu=4k, vls=4, and this succeeds.

Since we do not want to have this error message always displayed at driver
start when there are ConnectX2 HCAs on the host, we deprecate the error
message for this specific command/input_modifier/opcode_modifier/fw-status
to be debug.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>