fs/ubifs/: remove unnecessary new_valid_dev() checks

fs/ubifs/: remove unnecessary new_valid_dev() checks

new_valid_dev() always returns 1, so the !new_valid_dev() checks are not
needed.  Remove them.

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Acked-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>