riscv: Make SYS_SUPPORTS_HUGETLBFS depends on MMU

HUGETLBFS only used when MMU enabled, add the dependency.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
1 file changed