pwm: clps711x: Changing the compatibility string to match with the smallest supported chip

This patch changes the compatibility string to match with the smallest
supported chip (EP7209). Since the DT-support for this CPU is not yet
announced, this change is safe.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/pwm/cirrus,clps711x-pwm.txt

 * Cirris Logic CLPS711X PWM controller
 
 Required properties:
-- compatible: Shall contain "cirrus,clps711x-pwm".
+- compatible: Shall contain "cirrus,ep7209-pwm".
 - reg: Physical base address and length of the controller's registers.
 - clocks: phandle + clock specifier pair of the PWM reference clock.
 - #pwm-cells: Should be 1. The cell specifies the index of the channel.
 
 Example:
 	pwm: pwm@80000400 {
-		compatible = "cirrus,ep7312-pwm",
-			     "cirrus,clps711x-pwm";
+		compatible = "cirrus,ep7312-pwm", "cirrus,ep7209-pwm";
 		reg = <0x80000400 0x4>;
 		clocks = <&clks 8>;
 		#pwm-cells = <1>;

drivers/pwm/pwm-clps711x.c

@@ -155,7 +155,7 @@ static int clps711x_pwm_remove(struct platform_device *pdev)
 }
 
 static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
-	{ .compatible = "cirrus,clps711x-pwm", },
+	{ .compatible = "cirrus,ep7209-pwm", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);