cpu-exec: Purge all uses of ENV_GET_CPU()

cpu-exec: Purge all uses of ENV_GET_CPU()

Remove un-needed usages of ENV_GET_CPU() by converting the APIs to use
CPUState pointers and retrieving the env_ptr as minimally needed.

Scripted conversion for target-* change:

for I in target-*/cpu.h; do
    sed -i \
    's/\(^int cpu_[^_]*_exec(\)[^ ][^ ]* \*s);$/\1CPUState *cpu);/' \
    $I;
done

Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>