net/atlantic: consider EEPROM get/set offset

net/atlantic: consider EEPROM get/set offset

EEPROM get/set offset logic should take offset into account.
Data transfers to/from FW should also correctly use
dword based transfer interface, taking into account the
remainder.
We also check error code returned from FW.

Fixes: ce4e8d418097 ("net/atlantic: implement EEPROM get/set")
Cc: stable@dpdk.org
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: Pavel Belous <pavel.belous@aquantia.com>