selftests: vm: add migration to the .gitignore

Add newly added migration test object to .gitignore file.

Link: https://lkml.kernel.org/r/20220521094313.166505-1-usama.anjum@collabora.com
Fixes: 0c2d087 ("mm: add selftests for migration entries")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Muhammad Usama Anjum

tools/testing/selftests/vm/.gitignore

@@ -9,6 +9,7 @@ map_hugetlb
 map_populate
 thuge-gen
 compaction_test
+migration
 mlock2-tests
 mrelease_test
 mremap_dontunmap