cpufreq: intellidemand: Set MIN_LATENCY_MULTIPLIER to 20

Currently MIN_LATENCY_MULTIPLIER is set defined as 100 and so on a system with
transition latency of 1 ms, the minimum sampling time comes to be around 100 ms.
That is quite big if you want to get better performance for your system.

Redefine MIN_LATENCY_MULTIPLIER to 20 so that we can support 20ms sampling rate
for such platforms.

Change-Id: I2648a45be8dd8150bd7a9a3f84d0769528693637
Signed-off-by: faux123 <reioux@gmail.com>