Add rustup to Ubuntu 22.04

Some of the new TF-A visualization jobs require Rust/Cargo. This change
adds rustup (and consequently Cargo) to the dependencies so that they
are available for use within the TF-A CI scripts.

Change-Id: I051ea57226fd842e8d77c72d6702301cfd773db4
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/jammy-amd64-tf-a-build/Dockerfile b/jammy-amd64-tf-a-build/Dockerfile
index 3f34daa..30f4dee 100644
--- a/jammy-amd64-tf-a-build/Dockerfile
+++ b/jammy-amd64-tf-a-build/Dockerfile
@@ -4,7 +4,9 @@
 ENV DEBIAN_FRONTEND=noninteractive
 ENV NVM_DIR=/usr/local/nvm
 ENV TOOLS_DIR=/home/buildslave/tools
-ENV PATH=${TOOLS_DIR}/bin:${PATH}
+ENV RUSTUP_HOME=/usr/local/rustup
+ENV CARGO_HOME=/usr/local/cargo
+ENV PATH=${RUSTUP_HOME}/bin:${CARGO_HOME}/bin:${TOOLS_DIR}/bin:${PATH}
 ENV PLANTUML_JAR_PATH=/usr/share/plantuml/plantuml.jar
 ENV PKG_DEPS="\
     bc \
@@ -95,5 +97,8 @@
     apt clean ;\
     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 
+RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | \
+        sh -s -- --default-toolchain stable -y
+
 EXPOSE 22
 ENTRYPOINT ["/usr/sbin/setup-sshd"]