mtd: rawnand: intel: Add missing of_node_put() in ebu_nand_probe()

The 'chip_np' returned by of_get_next_child() with refcount decremented,
of_node_put() need be called in error path to decrease the refcount.

Fixes: bfc618fc ("mtd: rawnand: intel: Read the chip-select line from the correct OF node")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220924131010.957117-1-yangyingliang@huawei.com