genalloc: Fix a set of docs build warnings

Commit 795ee30648c7 ("lib/genalloc: introduce chunk owners") made a number
of changes to the genalloc API and implementation but did not update the
documentation to match, leading to these docs build warnings:

  ./lib/genalloc.c:1: warning: 'gen_pool_add_virt' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_alloc' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_free' not found
  ./lib/genalloc.c:1: warning: 'gen_pool_alloc_algo' not found

Fix these by updating the docs to match new function locations and names,
and by completing the update of one kerneldoc comment.

Fixes: 795ee30648c7 ("lib/genalloc: introduce chunk owners")
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/lib/genalloc.c b/lib/genalloc.c
index 9fc3129..24d20ca 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -472,7 +472,7 @@ void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
 EXPORT_SYMBOL(gen_pool_dma_zalloc_align);
 
 /**
- * gen_pool_free - free allocated special memory back to the pool
+ * gen_pool_free_owner - free allocated special memory back to the pool
  * @pool: pool to free to
  * @addr: starting address of memory to free back to pool
  * @size: size in bytes of memory to free