dt-bindings: hwmon: aspeed-pwm-tacho: Add reset node

The device tree bindings are updated to document the resets phandle, and
the example is updated to match what is expected for both the reset and
clock phandle.

Note that the bindings should have always had the reset controller, as
the hardware is unusable without it.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt

@@ -22,8 +22,9 @@ Required properties for pwm-tacho node:
 - compatible : should be "aspeed,ast2400-pwm-tacho" for AST2400 and
 	       "aspeed,ast2500-pwm-tacho" for AST2500.
 
-- clocks : a fixed clock providing input clock frequency(PWM
-	   and Fan Tach clock)
+- clocks : phandle to clock provider with the clock number in the second cell
+
+- resets : phandle to reset controller with the reset number in the second cell
 
 fan subnode format:
 ===================
@@ -48,19 +49,14 @@ Required properties for each child node:
 
 Examples:
 
-pwm_tacho_fixed_clk: fixedclk {
-	compatible = "fixed-clock";
-	#clock-cells = <0>;
-	clock-frequency = <24000000>;
-};
-
 pwm_tacho: pwmtachocontroller@1e786000 {
 	#address-cells = <1>;
 	#size-cells = <1>;
 	#cooling-cells = <2>;
 	reg = <0x1E786000 0x1000>;
 	compatible = "aspeed,ast2500-pwm-tacho";
-	clocks = <&pwm_tacho_fixed_clk>;
+	clocks = <&syscon ASPEED_CLK_APB>;
+	resets = <&syscon ASPEED_RESET_PWM>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_pwm0_default &pinctrl_pwm1_default>;