Starting with the ARMv7 Virtualization Extensions, the A32 and T32
instruction sets provide instructions "MSR (banked)" and "MRS
(banked)" which can be used to access registers for a mode other
than the current one:
 * R<m>_<mode>
 * ELR_hyp
 * SPSR_<mode>

Implement the missing instructions.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Acked-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1456762734-23939-1-git-send-email-peter.maydell@linaro.org