target-arm: Bring AArch64 debug CPU display of PSTATE into line with AArch32

The AArch64 debug CPU display of PSTATE as "PSTATE=200003c5 (flags --C-)"
on the end of the same line as the last of the general purpose registers
is unnecessarily different from the AArch32 display of PSR as
"PSR=200001d3 --C- A svc32" on its own line. Update the AArch64
code to put PSTATE in its own line and in the same format, including
printing the exception level (mode).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 1445883178-576-2-git-send-email-peter.maydell@linaro.org