hw/arm/highbank: Simplify code (memory region in device state) The memory region can be included by value instead of by reference in the device state. Signed-off-by: Stefan Weil <sw@weilnetz.de> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>