Introduce only one non-abstract type TYPE_ARM_CPU and do not touch
cp15 registers to not interfere with Peter's ongoing remodelling.
Embed CPUARMState as first (additional) field of ARMCPU.

Let CPUClass::reset() call cpu_state_reset() for now.
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>