HACK: ARM: disable sleeping while atomic warning in do_signal

ARM disables interrupts in do_signal, which triggers a warning in
try_to_freeze, see details at https://lkml.org/lkml/2011/8/23/221.
To prevent the warnings, add try_to_freeze_nowarn and call it from
do_signal.
cpufreq: ondemand: update sampling rate only on right CPUs
Fix cpufreq_gov_ondemand to skip CPU where another governor is used. The bug present itself as NULL pointer access on the mutex_lock() call, an can be reproduced on an SMP machine by setting the default governor to anything other than ondemand, setting a single CPU's governor to ondemand, then changing the sample rate by writing on:
 cpufreq: ondemand: 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.

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