[ARM] 5524/1: at91sam9g20ek: add i2c eeprom info

Add board information about on-board I2C eeprom AT24C512N at 0x50.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>