Add missing aeabi_memcpy.S file from llvm compiler-rt library [1]. This
is required for Aarch32 builds with clang.
[1] https://github.com/llvm/llvm-project.git
Change-Id: I7fd6ab1e81dd45d24afef49a3eb8fcdcbc5c082f
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>