ARM: dts: armada-xp: fix Armada XP boards NAND description

Commit 3b799199 ("ARM: dts:
armada-370-xp: update NAND node with new bindings") updated some
Marvell Armada DT description to use the new NAND controller bindings,
but did it incorrectly for a number of boards: armada-xp-gp,
armada-xp-db and armada-xp-lenovo-ix4-300d. Due to this, the NAND is
no longer detected on those platforms.

This commit fixes that by properly using the new NAND DT binding. This
commit was runtime-tested on Armada XP GP, the two other platforms are
only compile-tested.

Fixes: 3b799199

 ("ARM: dts: armada-370-xp: update NAND node with new bindings")
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>