target-arm: Dump 32-bit CPU state if 64 bit CPU is in AArch32

target-arm: Dump 32-bit CPU state if 64 bit CPU is in AArch32

For system mode, we may have a 64 bit CPU which is currently executing
in AArch32 state; if we're dumping CPU state to the logs we should
therefore show the correct state for the current execution state,
rather than hardwiring it based on the type of the CPU. For consistency
with how we handle translation, we leave the 32 bit dump function
as the default, and have it hand off control to the 64 bit dump code
if we're in AArch64 mode.

Reported-by: Rob Herring <rob.herring@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>