dt-bindings: arm: add cortex-a12 and cortex-a17 cpu compatible properties

As announced parts from ARM they will probably be used in socs shortly.
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/arm/cpus.txt

@@ -152,7 +152,9 @@ nodes to be present and contain the properties described below.
 			    "arm,cortex-a7"
 			    "arm,cortex-a8"
 			    "arm,cortex-a9"
+			    "arm,cortex-a12"
 			    "arm,cortex-a15"
+			    "arm,cortex-a17"
 			    "arm,cortex-a53"
 			    "arm,cortex-a57"
 			    "arm,cortex-m0"