docs: deprecated.rst: Update an example

vmalloc() has a 2-factor form. It is vmalloc_array().
So use another function as an example.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/3484e46180dd2cf05d993ff1a78b481bc2ad1f71.1687723931.git.christophe.jaillet@wanadoo.fr

Documentation/process/deprecated.rst

@@ -77,7 +77,7 @@ kzalloc() can be replaced with kcalloc().
 If no 2-factor form is available, the saturate-on-overflow helpers should
 be used::
 
-	bar = vmalloc(array_size(count, size));
+	bar = dma_alloc_coherent(dev, array_size(count, size), &dma, GFP_KERNEL);
 
 Another common case to avoid is calculating the size of a structure with
 a trailing array of others structures, as in::