ARM: qcom: Add MSM Legacy hotplug low power mode APIs

Add low power mode support for hotplug CPUs.

Remove pen release logic, forloop & gic pending
irqs print from legacy hotplug code.

Remove vfp_resume call as current vfp module has
pm notifiers.

Add 'cpu_can_disable' smp callback to enable hotplug
support for bootcore CPU

Change-Id: Ic830bbea1260c34bd383d7c07e2c6fef05677ded
Signed-off-by: Chinkit Kumar,Kirti Kumar Parmar <parma@codeaurora.org>