thinkpad_acpi: add the ability setting TPACPI_LED_NONE by quirk

Some new Lenovo or ThinkPad laptops don't have EC controllable LEDs,
their LED quirks are 0. This patch set led_supported=TPACPI_LED_NONE
when quirk equals 0.

Signed-off-by: Adam Lee <adam.lee@canonical.com>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>