bionic-amd64-tf-m-build: Install ArmClang 6.18

Required to support UBL licensing. Related to
https://linaro.atlassian.net/browse/TFC-198

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I77638fe2bcda1867636bab18d3ab3b82b23ad57f
diff --git a/bionic-amd64-tf-m-build/Dockerfile b/bionic-amd64-tf-m-build/Dockerfile
index 7f50f1e..4478a4e 100644
--- a/bionic-amd64-tf-m-build/Dockerfile
+++ b/bionic-amd64-tf-m-build/Dockerfile
@@ -18,6 +18,8 @@
 ENV GCC_11_2_PATH=${GCC_11_2_DIR}/bin
 ENV ARMCLANG_6_13_DIR=${COMPILER_DIR}/armclang-6-13
 ENV ARMCLANG_6_13_PATH=${ARMCLANG_6_13_DIR}/bin
+ENV ARMCLANG_6_18_DIR=${COMPILER_DIR}/armclang-6-18
+ENV ARMCLANG_6_18_PATH=${ARMCLANG_6_18_DIR}/bin
 ENV PKG_DEPS="\
     bison \
     build-essential \
@@ -69,6 +71,7 @@
 
 # Copy armclang toolchains
 COPY DS500-BN-00026-r5p0-15rel0.tar.gz /tmp/
+COPY ARMCompiler*.tar.gz /tmp/
 
 RUN set -ex ;\
     echo 'locales locales/locales_to_be_generated multiselect C.UTF-8 UTF-8, en_US.UTF-8 UTF-8 ' | debconf-set-selections ;\