Add a binary_point field to the gic emulation structure and support
setting/getting this register now when we have it. We don't actually
support interrupt grouping yet, oh well.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>