target/espressif: add profiling function for ESP32, ESP32-S2

Use the TRAX interface DEBUGPC if available.
Otherwise use default stop-and-go profiling.

ESP32: FT2232H+Linux: 97ksample/second @ 20mbps JTAG

Change-Id: I1dda43df2727b542b08e338f7f4ba63530844a4f
Signed-off-by: Richard Allen <rsaxvc@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8910
Reviewed-by: Samuel Obuch <samuel.obuch@espressif.com>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins

src/target/espressif/esp32.c

@@ -501,4 +501,5 @@ struct target_type esp32_target = {
 	.deinit_target = esp_xtensa_target_deinit,
 
 	.commands = esp32_command_handlers,
+	.profiling = esp_xtensa_profiling,
 };

src/target/espressif/esp32s2.c

@@ -538,4 +538,5 @@ struct target_type esp32s2_target = {
 	.deinit_target = esp_xtensa_target_deinit,
 
 	.commands = esp32s2_command_handlers,
+	.profiling = esp_xtensa_profiling,
 };