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>

linux-user/cpu_loop-common.h

@@ -24,7 +24,7 @@
 
 #define EXCP_DUMP(env, fmt, ...)                                        \
 do {                                                                    \
-    CPUState *cs = ENV_GET_CPU(env);                                    \
+    CPUState *cs = env_cpu(env);                                        \
     fprintf(stderr, fmt , ## __VA_ARGS__);                              \
     cpu_dump_state(cs, stderr, 0);                                      \
     if (qemu_log_separate()) {                                          \