Add remaining easy registers to iotkit-secctl:
* NSCCFG just routes its two bits out to external GPIO lines
* BRGINSTAT/BRGINTCLR/BRGINTEN can be dummies, because QEMU's
bus fabric can never report errors
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20180220180325.29818-18-peter.maydell@linaro.org