selftests: media_tests - Add media_device_open to .gitignore

Add media_device_open to .gitignore

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/media_tests/.gitignore

@@ -1 +1,2 @@
 media_device_test
+media_device_open