drm/amdgpu: Optimize end of non-contig VA ranges

Treat the last page in a non-contiguous range as part of the following
contiguous range.
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-and-tested-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -867,6 +867,8 @@ int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 					    pages_addr[idx - 1] + PAGE_SIZE))
 						break;
 				}
+				if (!contiguous)
+					count--;
 				num_entries = count *
 					AMDGPU_GPU_PAGES_IN_CPU_PAGE;
 			}