meta-romulus: Add fan monitor config

1. Enable fan monitor;
2. Add FanPwm interface;
3. Set the factor, offset for calculation from pwm to rpm

Tested: Verifid fan monitor works fine;
        Manually change pwm, fan monitor will set fan non-functional
        after a while; change pwm back, it will set fan functional
        again, as expected.

Change-Id: Ic56cbe291959368218b60c4a5b8e305f39ff7edb
Signed-off-by: Lei YU <mine260309@gmail.com>
2 files changed