radv: Fix sparse BO mapping merging.

If we merge a mapping with the mapping before it, we also need
to not only change the offset, but also the bo offset.

Fixes: 715df30a4e "radv/amdgpu: Add winsys implementation of virtual buffers."
Reviewed-by: Dave Airlie <airlied@redhat.com>

src/amd/vulkan/winsys/amdgpu/radv_amdgpu_bo.c

@@ -149,6 +149,7 @@ radv_amdgpu_winsys_bo_virtual_bind(struct radeon_winsys_bo *_parent,
 	if (parent->ranges[first].bo == bo && (!bo || offset - bo_offset == parent->ranges[first].offset - parent->ranges[first].bo_offset)) {
 		size += offset - parent->ranges[first].offset;
 		offset = parent->ranges[first].offset;
+		bo_offset = parent->ranges[first].bo_offset;
 		remove_first = true;
 	}