ntfs: fix uninitialized variable in ntfs_map_runlist_nolock

ntfs: fix uninitialized variable in ntfs_map_runlist_nolock

Smatch reported that ctx_needs_reset could be used uninitialized if
ntfs_map_runlist_nolock() fails early when a search context is provided.
Specifically, if the function returns -EIO because the attribute is
resident, the code jumps to err_out. This initializes ctx_needs_reset to
false to satisfy the static checker.

Reported-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>