mm/memremap: fix wrong function name above memremap_pages()

Fix the wrong function name dev_memremap_pages above memremap_pages() to
avoid confusion.  Minor readability improvement.

Link: https://lkml.kernel.org/r/20220607143621.58989-1-linmiaohe@huawei.com


Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>