ARM: dts: at91: nattis: use the correct compatible for the eeprom

The used part does contain an eeprom compatible with an Atmel 24c02
chip and it is from NXP, but it is not called 24c02. It's actually a
se97b chip. Adjust the compatible accordingly.

Fixes: 0e432389

 ("ARM: dts: at91: add devicetree for the Axentia Nattis with Natte power")
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>