wifi: atmel: Fix atmel_private_handler array size

Fix the atmel_private_handler to correctly sized (1 element) again. (I
should have checked the data segment for differences.) This had no
behavioral impact (no private callbacks), but it made a very large
zero-filled array.

Cc: Simon Kelley <simon@thekelleys.org.uk>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Fixes: 8af9d4068e86 ("wifi: atmel: Avoid clashing function prototypes")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221018023732.never.700-kees@kernel.org