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)
diff --git a/script/tf-coverity/common-def.sh b/script/tf-coverity/common-def.sh
index dc92d44..06971cc 100644
--- a/script/tf-coverity/common-def.sh
+++ b/script/tf-coverity/common-def.sh
@@ -65,8 +65,7 @@
 
 # Provide correct armclang toolchain based on environment
 set_armclang_toolchain() {
-    # FIXME: ARMCompiler 6.18 is symlinked to 6.17 until it is available on OpenCI.
-    local armclang_path="/home/buildslave/tools/armclang-6.17/bin"
+    local armclang_path="/home/buildslave/tools/armclang-6.18/bin"
 
     # if under arm enviroment, overide cross-compilation path
     is_arm_jenkins_env || upon "$local_ci" && armclang_path="/arm/warehouse/Distributions/FA/ARMCompiler/6.18/19/standalone-linux-x86_64-rel/bin"