arm64: dts: broadcom: bcmbca: Update router boards

Enable the nand controller and add WP pin connection property in actual
board dts as they are board level properties now that they are disabled
and moved out from SoC dtsi.

Also remove the unnecessary brcm,nand-has-wp property from AC5300 board.
This property is only needed for some old controller that this board
does not apply.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/linux-mtd/20240223034758.13753-10-william.zhang@broadcom.com