arm64: dts: broadcom: bcmbca: bcm4908: set brcm,wp-not-connected

arm64: dts: broadcom: bcmbca: bcm4908: set brcm,wp-not-connected

Every described BCM4908 board has WP pin not connected. This caused
problems for drivers since day 0 but there was no property to describe
that properly. Projects like OpenWrt were modifying Linux driver to deal
with it.

It's not clear if that is hardware limitation or just reference design
being copied over and over but this applies to all known / supported
BCM4908 boards. Handle it by marking WP as not connected by default.

Fixes: 2961f69f151c ("arm64: dts: broadcom: add BCM4908 and Asus GT-AC5300 early DTS files")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Link: https://lore.kernel.org/r/20240328093710.28206-1-zajec5@gmail.com
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>