MIPS: dts: qca: ar9132: use short references for dt nodes

MIPS: dts: qca: ar9132: use short references for dt nodes

Here are some Sascha Hauer's arguments for using aliases in the dts
files:

 - using aliases reduces the number of indentations in dts files;

 - dts files become independent of the layout of the dtsi files
   (it becomes possible to introduce another bus {} hierarchy between
   a toplevel bus and the devices when you have to);

 - less chances for typos. if &i2c2 does not exist you get an error.
   If instead you duplicate the whole path in the dts file a typo
   in the path will just create another node.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Cc: Alban Bedel <albeu@free.fr>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12873/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>