ARM: NSP: dts: fix NAND nodes names

[ Upstream commit 0484594be733d5cdf976f55a2d4e8d887f351b69 ]

This matches nand-controller.yaml requirements.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>