dt-bindings: mailbox: apple,mailbox: Add ASC mailboxes on Apple A11 and T2

dt-bindings: mailbox: apple,mailbox: Add ASC mailboxes on Apple A11 and T2

Add bindings for ASC mailboxes as found on Apple A11 and T2 SoCs. These
mailboxes are used for coprocessors including Secure Enclave Processor
(SEP), the NVMe coprocessor and the system management controller.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
Link: https://lore.kernel.org/r/20250821-t8015-nvme-v3-1-14a4178adf68@gmail.com
Signed-off-by: Sven Peter <sven@kernel.org>