dt-bindings: bus: ti-sysc: Add support for PRUSS SYSC type

The PRUSS module has a SYSCFG which is unique. The SYSCFG
has two additional unique fields called STANDBY_INIT and
SUB_MWAIT in addition to regular IDLE_MODE and STANDBY_MODE
fields. Add the bindings for this new sysc type.

Cc: Rob Herring <[e-mail]>
Signed-off-by: Roger Quadros <[e-mail]>
Signed-off-by: Suman Anna <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Tony Lindgren <[e-mail]>

Documentation/devicetree/bindings/bus/ti-sysc.txt

···
 		"ti,sysc-dra7-mcasp"
 		"ti,sysc-usb-host-fs"
 		"ti,sysc-dra7-mcan"
+		"ti,sysc-pruss"
 
 - reg		shall have register areas implemented for the interconnect
 		target module in question such as revision, sysc and syss

include/dt-bindings/bus/ti-sysc.h

···
 
 #define SYSC_DRA7_MCAN_ENAWAKEUP	(1 << 4)
 
+/* PRUSS sysc found on AM33xx/AM43xx/AM57xx */
+#define SYSC_PRUSS_SUB_MWAIT		(1 << 5)
+#define SYSC_PRUSS_STANDBY_INIT		(1 << 4)
+
 /* SYSCONFIG STANDBYMODE/MIDLEMODE/SIDLEMODE supported by hardware */
 #define SYSC_IDLE_FORCE			0
 #define SYSC_IDLE_NO			1