net: Convert move_addr_to_user() to scoped user access

net: Convert move_addr_to_user() to scoped user access

move_addr_to_user() is a critical functions that was converted to
masked user access by commit 1fb0e471611d ("net: remove one stac/clac
pair from move_addr_to_user()")

Convert it to scoped user access to simplify the code.

Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/36d7f2e7f504d620c1b88526b25ebc89e3cb61d9.1773142315.git.chleroy@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>