arm64: dts: rockchip: Make eeprom read-only for Radxa ROCK 3C/5A/5C

arm64: dts: rockchip: Make eeprom read-only for Radxa ROCK 3C/5A/5C

The BL24C16 EEPROM implemented on the Radxa ROCK 3C, 5A, and 5C [1]
[2] [3] is designed to have data written during factory programming
(regardless of whether data is actually written or not), and we at
Radxa permit users to read the data but not write to it. [4]
Therefore, we will add a read-only property to the eeprom node.

[1] https://dl.radxa.com/rock3/docs/hw/3c/v1400/radxa_rock_3c_v1400_schematic.pdf p.13
[2] https://dl.radxa.com/rock5/5a/docs/hw/radxa_rock5a_V1.1_sch.pdf p.19
[3] https://dl.radxa.com/rock5/5c/docs/hw/v1100/radxa_rock_5c_schematic_v1100.pdf p.18
[4] https://github.com/radxa/u-boot/blob/next-dev-v2024.10/drivers/misc/radxa-i2c-eeprom.c

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Link: https://patch.msgid.link/20260108034252.2713-1-naoki@radxa.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>