ext4: Convert __ext4_block_zero_page_range() to use a folio

Use folio APIs throughout.  Saves many calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230324180129.1220691-21-willy@infradead.org


Signed-off-by: Theodore Ts'o <tytso@mit.edu>