Add the FRE/FWE pins for the JZ4740.

These pins must be in function #0 for the NAND to work. The reason it
worked before was because the bootloader did set these pins to the
correct function beforehand.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20200607174243.2361664-1-paul@crapouillou.netSigned-off-by: Linus Walleij <linus.walleij@linaro.org>