ledc: Fix two bugs inside LEDC driver

1. Regression introduced when refactoring on clock sources selection (0d07f859).
   If channel configuration is called before timer configuration on C6, PWM signal may not be able to output.
2. Missing the improper fade parameter fix inside ledc_set_duty_and_update() function.

components/hal/esp32s3/include/hal/ledc_ll.h

@@ -33,6 +33,9 @@ extern "C" {
                                 LEDC_SLOW_CLK_RC_FAST, \
                               }
 
+#define LEDC_LL_GLOBAL_CLK_DEFAULT LEDC_SLOW_CLK_RC_FAST
+
+
 /**
  * @brief Set LEDC low speed timer clock
  *