cpu: Replace ENV_GET_CPU with env_cpu

Now that we have both ArchCPU and CPUArchState, we can define
this generically instead of via macro in each target's cpu.h.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

scripts/tracetool/format/tcg_helper_c.py

@@ -25,7 +25,7 @@ def vcpu_transform_args(args, mode):
     if mode == "code":
         return Arguments([
             # Does cast from helper requirements to tracing types
-            ("CPUState *", "ENV_GET_CPU(%s)" % args.names()[0]),
+            ("CPUState *", "env_cpu(%s)" % args.names()[0]),
         ])
     else:
         args = Arguments([