meta-ibm: Mihawk fan control support GPU thermal sensor

Mihawk can use GPU, so fan control must support GPU thermal sensor.

Tested: Fan speed is automatically controlled when using GPU

(From meta-ibm rev: 2ecdfbd9911c5df8909089d87774a768cfb06716)

Change-Id: I7a62dd349a72c1c3fb6dc314e7a011afb51e75b1
Signed-off-by: Ben Pai <Ben_Pai@wistron.com>
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>