forked from Mirrors/opensbi

If the system is defined from tlb_fifo_num_entries, the scratch may be too small to hold the fifo, so it is alloc through the heap. Signed-off-by: Xiang W <wxjstz@126.com> Signed-off-by: Xing Xiaoguang <xiaoguang.xing@sophgo.com> Reviewed-by: Anup Patel <anup@brainfault.org>