cxgb4: Use Firmware params to get buffer-group map

Buffer group mappings can be obtained using FW_PARAMs cmd for newer FW.

Since some of the bg_maps are obtained in atomic context, created another
t4_query_params_ns(), that wont sleep when awaiting mbox cmd completion.

Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Arjun Vynipadath <arjun@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>