ext4: convert ext4_da_do_write_end() to take a folio

There's nothing page-specific happening in ext4_da_do_write_end();
it's merely used for its refcount & lock, both of which are folio
properties.  Saves four calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231214053035.1018876-1-willy@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>