kselftest/arm64: Add missing file in .gitignore

The binary generated by check_hugetlb_options is missing in .gitignore
under the directory. Add it into the file so it won't be logged into
version control.

Signed-off-by: I-Hsin Cheng <richard120310@gmail.com>
Signed-off-by: Will Deacon <will@kernel.org>

Author: vax-r

tools/testing/selftests/arm64/mte/.gitignore

@@ -6,3 +6,4 @@ check_mmap_options
 check_prctl
 check_ksm_options
 check_user_mem
+check_hugetlb_options