bsd-user: Move per-cpu code into target_arch_cpu.h

Move cpu_loop() into target_cpu_loop(), and put that in
target_arch_cpu.h for each architecture.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

bsd-user/qemu.h

@@ -82,6 +82,7 @@ typedef struct TaskState {
     pid_t ts_tid;     /* tid (or pid) of this task */
 
     struct TaskState *next;
+    struct bsd_binprm *bprm;
     int used; /* non zero if used */
     struct image_info *info;