mach-msm: mpdecision: sysfs: check if cpu is offline before hotplugging it

Signed-off-by: showp1984 <showp1984@gmail.com>
mach-msm: mpdecision: don't turn off cpu1 if freq > idle

This fixes cpu1 being turned off though it is still working
with a high frequency. The idle_freq can be modified through sysfs.

Signed-off-by: showp1984 <showp1984@gmail.com>