linux-user: move mips/mips64 cpu loop to mips directory

No code change, only move code from main.c to
mips/cpu_loop.c.

Include mips/cpu_loop.c in mips64/cpu_loop.c
to avoid to duplicate code.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180411185651.21351-8-laurent@vivier.eu>

linux-user/mips64/cpu_loop.c

@@ -17,10 +17,4 @@
  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "qemu/osdep.h"
-#include "qemu.h"
-#include "cpu_loop-common.h"
-
-void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
-{
-}
+#include "../mips/cpu_loop.c"