Add NAND controller node to LD4, Pro4, sLD8, Pro5, and PXs2.
Set up pinctrl to enable 2 chip select lines except Pro4.  The CS1
for Pro4 is multiplexed with other peripherals such as UART2, so
I did not enable it.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>