eeprom: After eeprom_write g_file could point to a closed file
eeprom: After eeprom_write g_file could point to a closed file

Calling eeprom_write would either re-use g_file or newly open the
file and set g_file but it will close the file as well. This will
lead to other code using fseek/fread on a closed file.

On top of that the general rule for the eeprom code now is that
read and write may not be mixed (due caching and other bits).

telenoobie/osmo-bts,geosphere/osmo-bts,geosphere/osmo-bts,osmocom/osmo-bts,geosphere/osmo-bts,geosphere/osmo-bts,osmocom/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts,osmocom/osmo-bts