linux-user: fix for loopmount ioctl

In case a chrooted build uses XEN or KVM, a looped mount needs to be done to setup the chroot.
The ioctl for loop mount works correctly for arm, mips, ppc32 and sh4, so its now activated.
Signed-off-by: NRiku Voipio <riku.voipio@nokia.com>

linux-user/ioctls.h

@@ -312,10 +312,8 @@
   IOCTL(LOOP_CLR_FD, 0, TYPE_INT)
   IOCTL(LOOP_SET_STATUS, IOC_W, MK_PTR(MK_STRUCT(STRUCT_loop_info)))
   IOCTL(LOOP_GET_STATUS, IOC_W, MK_PTR(MK_STRUCT(STRUCT_loop_info)))
-#if 0 /* These have some problems - not fully tested */
   IOCTL(LOOP_SET_STATUS64, IOC_W, MK_PTR(MK_STRUCT(STRUCT_loop_info64)))
   IOCTL(LOOP_GET_STATUS64, IOC_W, MK_PTR(MK_STRUCT(STRUCT_loop_info64)))
-#endif
   IOCTL(LOOP_CHANGE_FD, 0, TYPE_INT)
 
   IOCTL(MTIOCTOP, IOC_W, MK_PTR(MK_STRUCT(STRUCT_mtop)))