merge.sh: Filter out mbedTLS files from coverage data

mbedTLS source is currently not in shared folder, so genhtml errors out
when producing per-source reports for it. We probably could get source
up there, but coverage reports for such 3rd-party files is probably
not useful in the 1st place, so filter it out instead.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
diff --git a/coverage-tool/coverage-reporting/merge.sh b/coverage-tool/coverage-reporting/merge.sh
index c2a3158..841c459 100755
--- a/coverage-tool/coverage-reporting/merge.sh
+++ b/coverage-tool/coverage-reporting/merge.sh
@@ -415,6 +415,9 @@
 if [ -n "$LOCAL_WORKSPACE" ]; then
     # Perform path translation specific to OpenCI tf-a-ci-gateway/tf-a-builder
     sed -i "s|SF:/home/buildslave/workspace/[^/]*|SF:$LOCAL_WORKSPACE|" $output_coverage_file
+    # Filter out 3rd-party component files which shouldn't be in the report
+    lcov -rc lcov_branch_coverage=1 -r $output_coverage_file '*/workspace/mbedtls/*' -o $output_coverage_file.tmp
+    mv $output_coverage_file.tmp $output_coverage_file
 fi
 cat $output_coverage_file
 # Generate branch coverage report