dt-bindings: power: reset: qcom: Add qcom,pm8998-pon compatibility line

Update bindings to support for qcom,pm8998-pon which uses gen2 pon

Cc: Andy Gross <[e-mail]>
Cc: David Brown <[e-mail]>
Cc: Bjorn Andersson <[e-mail]>
Cc: Amit Pundir <[e-mail]>
Cc: Rob Herring <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Sebastian Reichel <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Reviewed-by: Bjorn Andersson <[e-mail]>
Signed-off-by: John Stultz <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

Documentation/devicetree/bindings/power/reset/qcom,pon.txt

···
 -compatible: Must be one of:
 	"qcom,pm8916-pon"
 	"qcom,pms405-pon"
+	"qcom,pm8998-pon"
 
 -reg: Specifies the physical address of the pon register