feat(mcpwm): Set group clock prescale dynamically

MCPWM group clock pre scale was originally fixed to 2, which is
inconvenient. Set group clock prescale dynamically. Now the maximum
resolution of the MCPWM timer is up to 160MHz(when the prescale set
to 1). And add a resulotion config for MCPWM capture.

docs/en/api-reference/peripherals/mcpwm.rst

@@ -173,6 +173,13 @@ To allocate a capture timer, you can call :cpp:func:`mcpwm_new_capture_timer` fu
 
 - :cpp:member:`mcpwm_capture_timer_config_t::group_id` sets the MCPWM group ID. The ID should belong to [0, :c:macro:`SOC_MCPWM_GROUPS` - 1] range.
 - :cpp:member:`mcpwm_capture_timer_config_t::clk_src` sets the clock source of the capture timer.
+- :cpp:member:`mcpwm_capture_timer_config_t::resolution_hz` The driver internally will set a proper divider based on the clock source and the resolution. If it is set to ``0``, the driver will pick an appropriate resolution on its own, and you can subsequently view the current timer resolution via :cpp:func:`mcpwm_capture_timer_get_resolution`.
+
+.. only:: not SOC_MCPWM_CAPTURE_CLK_FROM_GROUP
+
+    .. note::
+
+        In {IDF_TARGET_NAME}, :cpp:member:`mcpwm_capture_timer_config_t::resolution_hz` parameter is invalid, the capture timer resolution is always equal to the :cpp:enumerator:`MCPWM_CAPTURE_CLK_SRC_APB`.
 
 The :cpp:func:`mcpwm_new_capture_timer` will return a pointer to the allocated capture timer object if the allocation succeeds. Otherwise, it will return error code. Specifically, when there are no free capture timer left in the MCPWM group, this function will return :c:macro:`ESP_ERR_NOT_FOUND` error. [1]_