cxgb4 : retrieve port information from firmware

issue get port information command to firmware to retrieve port
information and update if it is different from what was last
recorded and also add indication for supported link modes for
firmware port types FW_PORT_TYPE_SFP28, FW_PORT_TYPE_KR_SFP28,
FW_PORT_TYPE_CR4_QSFP.

Based on the original work by Casey Leedom <leedom@chelsio.com>

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