Add xtensa esp32 boards build support

1. Add xtensa esp32 gcc toolchains
2. Add xtensa esp32 boards into full testlist firstly

Signed-off-by: liuhaitao <liuhaitao@xiaomi.com>
diff --git a/cibuild.sh b/cibuild.sh
index 15e7649..2c70b7c 100755
--- a/cibuild.sh
+++ b/cibuild.sh
@@ -24,7 +24,7 @@
 tools=$WD/../tools
 prebuilt=$WD/../prebuilt
 
-install="gen-romfs gperf kconfig-frontends arm-gcc-toolchain mips-gcc-toolchain riscv-gcc-toolchain c-cache"
+install="gen-romfs gperf kconfig-frontends arm-gcc-toolchain mips-gcc-toolchain riscv-gcc-toolchain xtensa-esp32-gcc-toolchain c-cache"
 
 function add_path {
   PATH=$1:$PATH
@@ -107,6 +107,19 @@
   riscv64-unknown-elf-gcc --version
 }
 
+function xtensa-esp32-gcc-toolchain {
+  add_path $prebuilt/xtensa-esp32-elf/bin
+
+  if [ ! -f "$prebuilt/xtensa-esp32-elf/bin/xtensa-esp32-elf-gcc" ]; then
+    cd $prebuilt
+    wget https://dl.espressif.com/dl/xtensa-esp32-elf-gcc8_2_0-esp32-2019r1-rc2-linux-amd64.tar.xz
+    xz -d xtensa-esp32-elf-gcc8_2_0-esp32-2019r1-rc2-linux-amd64.tar.xz
+    tar xf xtensa-esp32-elf-gcc8_2_0-esp32-2019r1-rc2-linux-amd64.tar
+    rm xtensa-esp32-elf-gcc8_2_0-esp32-2019r1-rc2-linux-amd64.tar
+  fi
+  xtensa-esp32-elf-gcc --version
+}
+
 function c-cache {
   add_path $prebuilt/ccache/bin
 
diff --git a/testlist/full.dat b/testlist/full.dat
index df46889..d150249 100644
--- a/testlist/full.dat
+++ b/testlist/full.dat
@@ -36,3 +36,5 @@
 -sim:rpserver
 
 /x86
+
+/xtensa