Remove VM_WAIT

Remove VM_WAIT and related defines.  VM_WAIT hasn't been in FreeBSD base
since 11, remove it.

Author: zeising

drivers/gpu/drm/i915/intel_freebsd.c

@@ -197,11 +197,7 @@ remap_io_mapping(struct vm_area_struct *vma, unsigned long addr,
 			if (vm_page_insert(m, vm_obj, pidx)) {
 				vm_page_xunbusy(m);
 				VM_OBJECT_WUNLOCK(vm_obj);
-#ifdef VM_WAIT
-				VM_WAIT;
-#else
 				vm_wait(NULL);
-#endif
 				VM_OBJECT_WLOCK(vm_obj);
 				goto retry;
 			}