Refactor bcm2835_fb_mbox_push() to work by calling
bcm2835_fb_validate_config() and bcm2835_fb_reconfigure(),
so that config set this way is also validated.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180814144436.679-9-peter.maydell@linaro.org