Fix a long standing ASF heartbeat sending bug. The initial
implementation of heartbeat interval was 2 but there was typo which
caused the heartbeat is sent approximately every 5 seconds. This
caused unintended controller reset by firmware because firmware
thought OS was crashed.

Submitted by:	Floris Bos < info <> je-eigen-domein dot nl >
Tested by:	Andrzej Tobola < ato <> iem dot pw dot edu dot pl >

Use new handshake command for BCM5750 or new controllers.