dt-bindings: apmu: Document r8a7743 support

Document APMU and SMP enable method for RZ/G1M
(also known as r8a7743) SoC.
Signed-off-by: NBiju Das <biju.das@bp.renesas.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/power/renesas,apmu.txt

 DT bindings for the Renesas Advanced Power Management Unit
 
-Renesas R-Car line of SoCs utilize one or more APMU hardware units
+Renesas R-Car and RZ/G1 SoCs utilize one or more APMU hardware units
 for CPU core power domain control including SMP boot and CPU Hotplug.
 
 Required properties:
 
 - compatible: Should be "renesas,<soctype>-apmu", "renesas,apmu" as fallback.
 	      Examples with soctypes are:
+		- "renesas,r8a7743-apmu" (RZ/G1M)
 		- "renesas,r8a7790-apmu" (R-Car H2)
 		- "renesas,r8a7791-apmu" (R-Car M2-W)
 		- "renesas,r8a7792-apmu" (R-Car V2H)