mcpwm: don't use keyword operator

Closes https://github.com/espressif/esp-idf/issues/9510

tools/test_apps/system/cxx_build_test/main/CMakeLists.txt

@@ -1,4 +1,5 @@
 idf_component_register(SRCS cxx_build_test_main.cpp
                             test_soc_reg_macros.cpp
                        INCLUDE_DIRS "."
+                       PRIV_REQUIRES driver
                        REQUIRES soc)

tools/test_apps/system/cxx_build_test/main/cxx_build_test_main.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: Unlicense OR CC0-1.0
  */
 #include <stdio.h>
+#include "driver/mcpwm_prelude.h"
 
 extern "C" void app_main(void)
 {