ARM: dts: vf610-zii-ssmb-spu3: Fix W=1 level warnings

Fix a couple of things that were causing warning when building DTB
with W=1.

Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: cphealy@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>