target/espressif: add semihosting support

ARM semihosting + some custom syscalls implemented for
Espressif chips (ESP32, ESP32-S2, ESP32-S3)

Signed-off-by: Erhan Kurubas <erhan.kurubas@espressif.com>
Change-Id: Ic8174cf1cd344fa16d619b7b8405c9650e869443
Reviewed-on: https://review.openocd.org/c/openocd/+/7074
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

tcl/target/esp_common.cfg

@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Common ESP chips definitions
+
+if { [info exists ESP_SEMIHOST_BASEDIR] } {
+	set _SEMIHOST_BASEDIR $ESP_SEMIHOST_BASEDIR
+} else {
+	# by default current dir (when OOCD has been started)
+	set _SEMIHOST_BASEDIR "."
+}