To update an entry when SFP database is in the eeprom, particular entry
is searched then simply updated.
On the other hand, when SFP database is in the flash simple update is
not possible. First old database is copied to the memory, then updated in
memory. After, the erase of the entire flash block is performed. At the end
updated information is written into the flash.
Signed-off-by: Adam Wujek <adam.wujek@cern.ch>