Jammy: add llvm dependency

The previous setup downloaded both clang and llvm manually, but llvm was
left out. Add it back

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: Iec5faab0149fcdb9ece1e42904e8fc97652e6ad4
diff --git a/jammy-amd64-tf-a-build/Dockerfile b/jammy-amd64-tf-a-build/Dockerfile
index e5b1e86..061e47a 100644
--- a/jammy-amd64-tf-a-build/Dockerfile
+++ b/jammy-amd64-tf-a-build/Dockerfile
@@ -12,6 +12,7 @@
     bison \
     build-essential \
     clang \
+    llvm \
     clang-tools \
     cpio \
     curl \