MAINTAINERS: exec: Add auxvec.h UAPI

Changes to auxiliary vectors would be best reviewed by the exec/binfmt
maintainers.

Link: https://lore.kernel.org/r/20241031220833.work.539-kees@kernel.org
Reviewed-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Kees Cook <kees@kernel.org>

Author: kees

MAINTAINERS

@@ -8501,6 +8501,7 @@ F:	fs/tests/binfmt_*_kunit.c
 F:	fs/tests/exec_kunit.c
 F:	include/linux/binfmts.h
 F:	include/linux/elf.h
+F:	include/uapi/linux/auxvec.h
 F:	include/uapi/linux/binfmts.h
 F:	include/uapi/linux/elf.h
 F:	tools/testing/selftests/exec/