greybus: manifest: be coherent with protocol name

remane protocol define from GREYBUS_PROTOCOL_LED to GREYBUS_PROTOCOL_LIGHTS to
be coherent with the specification.

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>