tf-coverity/common-def.sh: Fix FIXME for ArmClang 6.17 -> 6.18 symlink

We now have real 6.18 available, so use just it.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Id2a3893e9477ab6f116e4bacc7d3e5a1cbe88918
(cherry picked from commit 577a78844741a01ea28ceaeb9318065134e6633c)
1 file changed