fix(build): update clang target for aarch64

With the LLVM toolchain delivered by Arm [1], the target aarch64-elf
which is defaulting to aarch64-unknown-unknown-elf is now unknown.
Replace it with aarch64-unknown-none-elf.

[1]: https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/releases/tag/release-19.1.5

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I5a0fad1ee29838ef2c3a1bc8ecfba05aacf0a6d6
1 file changed