driver/mcpwm: add an option to capture on both edges.
driver/mcpwm: add an option to capture on both edges.

However, The functionality of capturing on both edges is alternatively done with passing in the two flags ORed together: MCPWM_NEG_EDGE|MCPWM_POS_EDGE

closes https://github.com/espressif/esp-idf/issues/4446
closes https://github.com/espressif/esp-idf/issues/2943

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf