If doing big-endian linux-user mode, set both the CPSR.E and SCTLR.E0E
bits. This sets big-endian mode for data accesses.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>