Binding for Qualcomm Atheros AR7xxx/AR9XXX SoC

Each device tree must specify a compatible value for the AR SoC
it uses in the compatible property of the root node. The compatible
value must be one of the following values:

- qca,ar7130
- qca,ar7141
- qca,ar7161
- qca,ar7240
- qca,ar7241
- qca,ar7242
- qca,ar9130
- qca,ar9132
- qca,ar9330
- qca,ar9331
- qca,ar9341
- qca,ar9342
- qca,ar9344
- qca,qca9556
- qca,qca9558

Add bindings for the SoC of the ATH79 family
DEVICETREE: Add bindings for the SoC of the ATH79 family

Signed-off-by: Alban Bedel <08cd4c4b74f2a6d260dcb581967005084d725085@free.fr>
Cc: 562397917b9a8bf316569a848858b12fb417723f@linux-mips.org
Signed-off-by: Ralf Baechle <92f48d309cda194c8eda36aa8f9ae28c488fa208@linux-mips.org>
