feat(mcpwm): MCPWM event comparator driver

In esp32p4, the MCPWM has a new feature, mainly ETM-oriented.
Each operator has two event comparators, can generate an event
when the count value of the timer that operator connects is equal
to the value of event comparator.

components/esp_hw_support/include/esp_private/etm_interface.h

@@ -24,6 +24,7 @@ typedef enum {
     ETM_TRIG_PERIPH_GDMA,     /*!< ETM trigger source: GDMA */
     ETM_TRIG_PERIPH_GPTIMER,  /*!< ETM trigger source: GPTimer */
     ETM_TRIG_PERIPH_SYSTIMER, /*!< ETM trigger source: Systimer */
+    ETM_TRIG_PERIPH_MCPWM,    /*!< ETM trigger source: MCPWM */
 } etm_trigger_peripheral_t;
 
 /**