target: add Espressif ESP32-S2 basic support

ESP32-S2 is a single core Xtensa chip.
Not full featured yet. Some of the missing functionality:
-Semihosting
-Flash breakpoints
-Flash loader
-Apptrace
-FreeRTOS

Signed-off-by: Erhan Kurubas <erhan.kurubas@espressif.com>
Change-Id: I2fb32978e801af5aa21616c581691406ad7cd6bb
Reviewed-on: https://review.openocd.org/c/openocd/+/6940
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-by: Ian Thompson <ianst@cadence.com>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins

tcl/board/esp32s2-kaluga-1.cfg

@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Example OpenOCD configuration file for ESP32-S2 Kaluga board.
+#
+# For example, OpenOCD can be started for ESP32-S2 debugging on
+#
+#   openocd -f board/esp32s2-kaluga-1.cfg
+#
+
+source [find interface/ftdi/esp32s2_kaluga_v1.cfg]
+source [find target/esp32s2.cfg]
+
+# The speed of the JTAG interface, in kHz. If you get DSR/DIR errors (and they
+# do not relate to OpenOCD trying to read from a memory range without physical
+# memory being present there), you can try lowering this.
+# On ESP32-S2, this can go as high as 20MHz if CPU frequency is 80MHz, or 26MHz
+# if CPU frequency is 160MHz or 240MHz.
+adapter speed 20000