meta-romulus: Add fan presence yaml config

Romulus has 3 fans using aspeed fan tacho, and has no GPIOs to detect
fan presences.

So assuming the fans are present as long as fan tach is there.

Change-Id: I60f36f8127a437511fde22a4c45458b70b4074ed
Signed-off-by: Lei YU <mine260309@gmail.com>
2 files changed