highmem: Rename put_and_unmap_page() to unmap_and_put_page()

With commit 849ad04c ("new helper: put_and_unmap_page()"), Al Viro
introduced the put_and_unmap_page() to use in those many places where we
have a common pattern consisting of calls to kunmap_local() +
put_page().

Obviously, first we unmap and then we put pages. Instead, the original
name of this helper seems to imply that we first put and then unmap.

Therefore, rename the helper and change the only known upstreamed user
(i.e., fs/sysv) before this helper enters common use and might become
difficult to find all call sites and instead easy to break the builds.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Message-Id: <20230602103307.5637-1-fmdefrancesco@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>