target-arm: move AArch32 SCR into security reglist

Define a new ARM CP register info list for the ARMv7 Security Extension
feature. Register that list only for ARM cores with Security Extension/EL3
support. Moving AArch32 SCR into Security Extension register group.

Signed-off-by: Sergey Fedorov <s.fedorov@samsung.com>
Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch>
Signed-off-by: Greg Bellows <greg.bellows@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1416242878-876-9-git-send-email-greg.bellows@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
