mm: remove stray references to struct pagevec

mm: remove stray references to struct pagevec

Patch series "mm: Remove stray references to pagevec", v2.

struct pagevec was removed in commit 1e0877d58b1e ("mm: remove struct
pagevec").  Remove any stray references to it and rename relevant files
and macros accordingly.

While at it, remove unnecessary #includes of pagevec.h (now folio_batch.h)
in .c files.  There are probably more of these that could be removed in .h
files, but those are more complex to verify.

This patch (of 4):

struct pagevec was removed in commit 1e0877d58b1e ("mm: remove struct
pagevec").  Remove remaining forward declarations and change
__folio_batch_release()'s declaration to match its definition.

Link: https://lkml.kernel.org/r/20260225-pagevec_cleanup-v2-0-716868cc2d11@columbia.edu
Link: https://lkml.kernel.org/r/20260225-pagevec_cleanup-v2-1-716868cc2d11@columbia.edu
Signed-off-by: Tal Zussman <tz2294@columbia.edu>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Chris Li <chrisl@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>