jammy-amd64-tf-a-build-lts2.8: Remove ArmClang 6.17

As we switched to 6.18. This follows similar change in the upstream image.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Icff23122fce5628ca3b1785eff27d2c311a4cfb6
2 files changed