ARM: dts: rockchip: Remove more clock-names from PWM nodes

A test with the command below gives this error:
/arch/arm/boot/dts/rk3228-evb.dt.yaml:
pwm@110b0020: clock-names: ['pwm'] is too short

Devices with only one PWM clock use it to both to derive the functional
clock for the device and as the bus clock. The driver does not need
"clock-names" to get a handle, so remove them all.

make ARCH=arm dtbs_check
DT_SCHEMA_FILES=Documentation/devicetree/bindings/pwm/pwm-rockchip.yaml
Signed-off-by: NJohan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20210510172911.6763-1-jbx6244@gmail.comSigned-off-by: NHeiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/rk322x.dtsi

@@ -379,7 +379,6 @@
 		reg = <0x110b0000 0x10>;
 		#pwm-cells = <3>;
 		clocks = <&cru PCLK_PWM>;
-		clock-names = "pwm";
 		pinctrl-names = "default";
 		pinctrl-0 = <&pwm0_pin>;
 		status = "disabled";
@@ -390,7 +389,6 @@
 		reg = <0x110b0010 0x10>;
 		#pwm-cells = <3>;
 		clocks = <&cru PCLK_PWM>;
-		clock-names = "pwm";
 		pinctrl-names = "default";
 		pinctrl-0 = <&pwm1_pin>;
 		status = "disabled";
@@ -401,7 +399,6 @@
 		reg = <0x110b0020 0x10>;
 		#pwm-cells = <3>;
 		clocks = <&cru PCLK_PWM>;
-		clock-names = "pwm";
 		pinctrl-names = "default";
 		pinctrl-0 = <&pwm2_pin>;
 		status = "disabled";
@@ -412,7 +409,6 @@
 		reg = <0x110b0030 0x10>;
 		#pwm-cells = <2>;
 		clocks = <&cru PCLK_PWM>;
-		clock-names = "pwm";
 		pinctrl-names = "default";
 		pinctrl-0 = <&pwm3_pin>;
 		status = "disabled";