ntfs3: use folios more in ntfs_compress_write()

Remove the local 'page' variable and do everything in terms of folios. 
Removes the last user of copy_page_from_iter_atomic() and a hidden call to
compound_head() in ClearPageDirty().

Link: https://lkml.kernel.org/r/20250514170607.3000994-3-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>