sysmo: Fix compiler warnings in eeprom.c
sysmo: Fix compiler warnings in eeprom.c

This avoids compiler warnings like

../../src/osmo-bts-sysmo/eeprom.c: In function ‘eeprom_WriteSysInfo’:
../../src/osmo-bts-sysmo/eeprom.c:605:58: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
             err = eeprom_write( EEPROM_CFG_START_ADDR + ((uint32_t)&ee.cfg.v1.sysInfo - (uint32_t)&ee), sizeof(ee.cfg.v1.sysInfo), (const char *) &ee.cfg.v1.sysInfo );

Change-Id: Ic748038e6f25ec18ccb4a2f2503ca567fb00a586

osmocom/osmo-bts,osmocom/osmo-bts,osmocom/osmo-bts