[ATfE] Disable use of zstd when building the toolchain (#108)

This patch disables the use of zstd when building the toolchain, as
using it creates an extra dependency on the `libzstd` shared library
which is not guaranteed to be present on all supported platforms.

Author: pratlucas

arm-software/embedded/CMakeLists.txt

@@ -239,6 +239,7 @@ set(LLVM_DEFAULT_TARGET_TRIPLE aarch64-linux-gnu CACHE STRING "")
 set(LLVM_APPEND_VC_REV OFF CACHE BOOL "")
 set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB OFF CACHE BOOL "")
+set(LLVM_ENABLE_ZSTD OFF CACHE BOOL "")
 set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
 
 # Default to a release build