ARM: dts: stm32: Add configuration EEPROM on AV96

The board has an EEPROM on the same I2C bus as PMIC, at address 0x53.
The EEPROM contains the board MAC address.

Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Change-Id: I340a0675c11e4599968b2e3ef0515fb8da8d7b42