ghost: Balance out input boost tunables

* 1.6 GHz is quite a bit, tone it down to 1.2 GHz while increasing the duration to half a second, maintaining butter.
* Prevent clock frequency from jumping around too much by increasing timer rate
* Decrease the timer slack duration so that the frequency won't stay on 1.7 GHz for too long

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>