Convert the passed page to a folio and use it throughout. Removes
a use of fscrypt_is_bounce_page(), which we're trying to remove.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>