The EXTRA record allows for additional space to be allocated
beyon what is currently reserved. Add code to emit and read
this record type.
Nothing uses extra space yet.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180303143823.27055-5-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>