selftest/lkdtm: Use local .gitignore

Commit 68ca0fd272da ("selftest/lkdtm: Don't pollute 'git status'")
introduced patterns for git to ignore files generated in
tools/testing/selftests/lkdtm/

Use local .gitignore file instead of using the root one.

Fixes: 68ca0fd272da ("selftest/lkdtm: Don't pollute 'git status'")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
diff --git a/.gitignore b/.gitignore
index 2763fce..72ef86a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -100,10 +100,6 @@
 /include/ksym/
 /arch/*/include/generated/
 
-# Generated lkdtm tests
-/tools/testing/selftests/lkdtm/*.sh
-!/tools/testing/selftests/lkdtm/run.sh
-
 # stgit generated dirs
 patches-*
 
diff --git a/tools/testing/selftests/lkdtm/.gitignore b/tools/testing/selftests/lkdtm/.gitignore
new file mode 100644
index 0000000..f262126
--- /dev/null
+++ b/tools/testing/selftests/lkdtm/.gitignore
@@ -0,0 +1,2 @@
+*.sh
+!run.sh