v8.1M introduces a new TRD flag in the CCR register, which enables
checking for stack frame integrity signatures on SG instructions.
This bit is not banked, and is always RAZ/WI to Non-secure code.
Adjust the code for handling CCR reads and writes to handle this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201119215617.29887-23-peter.maydell@linaro.org