ath5k: support LED's on emachines E510 notebook

Add vendor ID for AMBIT and use it to set the ath5k LED gpio.

base.c:
Changes-licensed-under: 3-Clause-BSD

Signed-off-by: Tulio Magno Quites Machado Filho <tuliom@gmail.com>
Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>