net: prestera: acl: make read-only array client_map static const

Don't populate the read-only array client_map  on the stack but
instead make it static const. Also makes the object code a little
smaller.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220307221349.164585-1-colin.i.king@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>