target-arm: Add support for Cortex-R5

target-arm: Add support for Cortex-R5

Introduce a CPU model for the Cortex R5 processor. ARMv7 with MPU,
and both thumb and ARM div instructions.

Also implement dummy ATCM and BTCM. These CPs are defined for R5 but
don't have a lot of meaning in QEMU yet. Raz them so the guest can
proceed if they are read. The TCM registers will return a size of 0,
indicating no TCM.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: efe213163e6800578494aba864ac30329de4d396.1434501320.git.peter.crosthwaite@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>