tf-coverity: exclude io_dummy.c file for the coverage

None of the upstream platform using io_dummy.c file hence
exclude it for the coverage.

Change-Id: I8df7d81166451c2a11759c2511ea7f62acd143ea
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/script/tf-coverity/coverity_tf_conf.py b/script/tf-coverity/coverity_tf_conf.py
index 949b34f..477ddc9 100644
--- a/script/tf-coverity/coverity_tf_conf.py
+++ b/script/tf-coverity/coverity_tf_conf.py
@@ -108,4 +108,8 @@
     # Exclude the following files used for STM32MP host tools (fiptool and cert_create)
     ("plat/st/stm32mp1/plat_def_uuid_config.c ", "Used to build STM32MP fiptool"),
     ("plat/st/stm32mp1/stm32mp1_tbb_cert.c", "Used to build STM32MP cert_create"),
+
+    # Exclude the IO files
+    ("drivers/io/io_dummy.c ", "None of the upstream platforms using this file"),
+
 ]