ntfs3: serve as alias for the legacy ntfs driver

Johan Hovold reported that removing the legacy ntfs driver broke boot
for him since his fstab uses the legacy ntfs driver to access firmware
from the original Windows partition.

Use ntfs3 as an alias for legacy ntfs if CONFIG_NTFS_FS is selected.
This is similar to how ext3 is treated.

Link: https://lore.kernel.org/r/Zf2zPf5TO5oYt3I3@hovoldconsulting.com
Link: https://lore.kernel.org/r/20240325-hinkriegen-zuziehen-d7e2c490427a@brauner


Fixes: 7ffa8f3d ("fs: Remove NTFS classic")
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johan Hovold <johan@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>