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>

target-sh4/cpu.h

@@ -193,7 +193,7 @@ typedef struct CPUSH4State {
 
 void sh4_translate_init(void);
 SuperHCPU *cpu_sh4_init(const char *cpu_model);
-int cpu_sh4_exec(CPUSH4State * s);
+int cpu_sh4_exec(CPUState *s);
 int cpu_sh4_signal_handler(int host_signum, void *pinfo,
                            void *puc);
 int superh_cpu_handle_mmu_fault(CPUState *cpu, vaddr address, int rw,