ntfs: Place check before dereference

ntfs: Place check before dereference

The variable ni has the possiblity of being null and is checked for it
but, only after it was dereferenced in a log message.

Put check before dereference.

Detected by Smatch:
fs/ntfs/attrib.c:2115 ntfs_resident_attr_record_add() warn:
variable dereferenced before check 'ni' (see line 2111)

fs/ntfs/attrib.c:2237 ntfs_non_resident_attr_record_add() warn:
variable dereferenced before check 'ni' (see line 2232)

Signed-off-by: Ethan Tidmore <ethantidmore06@gmail.com>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>