state: find device node from device path, not from device node path
The device node path may change from the internal device tree to the
one Linux is started with, so using this path to fixup the tree is
not very robust. Instead, use of_find_node_by_devpath() which has
been created for exactly this purpose.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>