mm/fs: convert inode_attach_wb() to take a folio

mm/fs: convert inode_attach_wb() to take a folio

Patch series "Writeback folio conversions".

Remove more calls to compound_head() by passing folios around instead of
pages.

This patch (of 2):

The only caller of inode_attach_wb() which doesn't pass NULL already has a
folio, so convert the whole call-chain to take folios.

Link: https://lkml.kernel.org/r/20230116192507.2146150-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230116192507.2146150-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>