rtos_sdk: docs: add aocpu (t5w,a5,a4,txhd2,s1a) access limitation [1/1]

PD#SWPL-132819

Problem:
add aocpu access limitation docs.

Solution:
add aocpu access limitation docs in arch/riscv.

Verify:
make docs

Change-Id: Ic54a506f1a9687978124facbbf608cdaa0d264cc
Signed-off-by: bangzheng.liu <bangzheng.liu@amlogic.com>
6 files changed