esp/ci: Update 'xtensa-clang-toolchain' ref

Author: gerekon

.gitlab-ci.yml

@@ -19,7 +19,7 @@ variables:
   BINUTILS_REF: "esp-2022r1-binutils"
   XTENSA_OVERLAYS_REF: "master"
   LLVM_GCC_TESTSUITE_REF: "esp-16.0.0-20230425"
-  XTENSA_CLANG_TOOLCHAIN_REF: "esp-15.0.0-20221201"
+  XTENSA_CLANG_TOOLCHAIN_REF: "esp-16.0.0-20230502"
 
   CROSS_ARM_IMAGE: $CI_DOCKER_REGISTRY/llvm-build-cross-arm:1
   PLATFORM_NAME_LINUX: "linux-amd64"