Revert "ubifs: Fix out-of-bounds memory access caused by abnormal value of node_len"

This reverts commit acc5af3e ("ubifs: Fix out-of-bounds memory access caused by abnormal value of node_len")

No need to avoid memory oob in dumping for data node alone. Later, node
length will be passed into function 'ubifs_dump_node()' which replaces
all node dumping places.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>