Add DeviceRequests to HostConfig to support NVIDIA GPUs

This patch hard-codes support for NVIDIA GPUs.
In a future patch it should move out into its own Device Plugin.

Signed-off-by: Tibor Vass <tibor@docker.com>

daemon/errors.go

@@ -80,6 +80,17 @@ func (e invalidIdentifier) Error() string {
 
 func (invalidIdentifier) InvalidParameter() {}
 
+type incompatibleDeviceRequest struct {
+	driver string
+	caps   [][]string
+}
+
+func (i incompatibleDeviceRequest) Error() string {
+	return fmt.Sprintf("could not select device driver %q with capabilities: %v", i.driver, i.caps)
+}
+
+func (incompatibleDeviceRequest) InvalidParameter() {}
+
 type duplicateMountPointError string
 
 func (e duplicateMountPointError) Error() string {