selftests: add .gitignore for efivarfs

Signed-off-by: Yuan Sun <sunyuan3@huawei.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/efivarfs/.gitignore

@@ -0,0 +1,2 @@
+create-read
+open-unlink