dt-bindings: omap: Add clock-output-names and #clock-cells

This allows us to use clock-output-names for the clock manager instance
name instead of relying on non-standard node names.

Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Tero Kristo <kristo@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Rob Herring <robh@kernel.org>
Message-Id: <20220203112337.19821-1-tony@atomide.com>

Documentation/devicetree/bindings/arm/omap/prcm.txt

@@ -31,12 +31,17 @@ Required properties:
 		(base address and length)
 - clocks:	clocks for this module
 - clockdomains:	clockdomains for this module
+- #clock-cells: From common clock binding
+- clock-output-names: From common clock binding
+
 
 Example:
 
-cm: cm@48004000 {
+cm: clock@48004000 {
 	compatible = "ti,omap3-cm";
 	reg = <0x48004000 0x4000>;
+	#clock-cells = <0>;
+	clock-output-names = "cm";
 
 	cm_clocks: clocks {
 		#address-cells = <1>;