ARM: dts: sh73a0: Remove CMT renesas,channels-mask

Update the DTS to remove the now deprecated "renesas,channels-mask"
property.

The channel information is now kept in the device driver and can easily
be determined based on the compat string.
Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/sh73a0.dtsi

@@ -100,9 +100,6 @@ cmt1: timer@e6138000 {
 		clocks = <&mstp3_clks SH73A0_CLK_CMT1>;
 		clock-names = "fck";
 		power-domains = <&pd_c5>;
-
-		renesas,channels-mask = <0x3f>;
-
 		status = "disabled";
 	};