mm/memory: convert do_page_mkwrite() to use folios

Saves one implicit call to compound_head().

Link: https://lkml.kernel.org/r/20230706163847.403202-1-sidhartha.kumar@oracle.com


Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>