mm: fix kernel-doc warning from tlb_flush_rmaps()

Patch series "Improve mm documentation".

If you build with W=1, kernel-doc complains about tlb_flush_rmaps().  Then
I ran scripts/find-unused-docs.sh against mm/ and found a large number of
files which weren't included in the ReST documentation.  I fixed up a
couple of them, and added all those without erros to the rst files. 
There's a lot more work to do to organise all of this, but at least now if
we have documentation that refers to these functions, we'll get a nice
link to them.


This patch (of 4):

The vma parameter wasn't described.

Link: https://lkml.kernel.org/r/20230818200630.2719595-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230818200630.2719595-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Matthew Wilcox (Oracle)

mm/mmu_gather.c

@@ -63,6 +63,7 @@ static void tlb_flush_rmap_batch(struct mmu_gather_batch *batch, struct vm_area_
 /**
  * tlb_flush_rmaps - do pending rmap removals after we have flushed the TLB
  * @tlb: the current mmu_gather
+ * @vma: The memory area from which the pages are being removed.
  *
  * Note that because of how tlb_next_batch() above works, we will
  * never start multiple new batches with pending delayed rmaps, so