target/arm: Add AIRCR to vmstate struct

target/arm: Add AIRCR to vmstate struct

In commit commit 3b2e934463121 we added support for the AIRCR
register holding state, but forgot to add it to the vmstate
structs. Since it only holds r/w state if the security extension
is implemented, we can just add it to vmstate_m_security.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180209165810.6668-10-peter.maydell@linaro.org