linux-user: Clean up interim solution for exit syscall

After all target CPUs have been QOM'ified, we no longer need an #ifdef
to switch between object_delete() and g_free() in NPTL thread exit.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

linux-user/syscall.c

@@ -5045,11 +5045,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                         NULL, NULL, 0);
           }
           thread_env = NULL;
-#ifdef ENV_GET_CPU
           object_delete(OBJECT(ENV_GET_CPU(cpu_env)));
-#else
-          g_free(cpu_env);
-#endif
           g_free(ts);
           pthread_exit(NULL);
       }