coverity: include rest of the platforms

Include the rest of current tf-m platforms. This change yielded to
coverity source code coverage to 46% [1].

[1] https://ci.staging.trustedfirmware.org/job/lsandov1-tf-m-coverity/28/console

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: I882782e90af8a6c6b414437796eac212cffcb618
diff --git a/script/tf-coverity/coverity_tf_conf.py b/script/tf-coverity/coverity_tf_conf.py
index ecb692a..2edc324 100644
--- a/script/tf-coverity/coverity_tf_conf.py
+++ b/script/tf-coverity/coverity_tf_conf.py
@@ -14,4 +14,7 @@
 #   describing the file(s) to exclude.
 # - description aims at providing the reason why the files are expected
 #   to be excluded.
-exclude_paths = []
+exclude_paths = [
+    ("platform/ext/.*", "3rd party libraries will not be fixed")
+    ("lib/ext/.*", "3rd party libraries will not be fixed"),
+]