qed: add support for Forward Error Correction

Add all necessary routines for reading supported FEC modes from NVM and
querying FEC control to the MFW (if the running version supports it).

Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>