fixes a bug in the eeprom emulation for stm32 that caused crashes when the first sector was full.
fixes a bug in the eeprom emulation for stm32 that caused crashes when the first sector was full.

bakerstu/openmrn,bakerstu/openmrn,bakerstu/openmrn,bakerstu/openmrn,bakerstu/openmrn,bakerstu/openmrn