cxgb4: Fix FW flash errors

commit 96ac18f1 ("cxgb4: Add support for new flash parts")
removed initialization of adapter->params.sf_fw_start causing issues
while flashing firmware to card. We no longer need sf_fw_start
in adapter->params as we already have macros defined for FW flash
addresses.

Fixes: 96ac18f1

 ("cxgb4: Add support for new flash parts")
Signed-off-by: Arjun Vynipadath <arjun@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>