Fix warnings generated from the kindle-mx50 dts when used in linux with W=1:
unit names should not have leading "0x"; reg property given, but no unit name;
use stdout-path instead of linux,stdout-path.
Also move the regulator-fixed node to the root node to match the convention.

Signed-off-by: Alexander Kurz <akurz@blala.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>