msm: idle-v7: Separate PC termination for hotplug

When a core is power collapsed as a part of hotplug the state of the CPU
isn't restored and hence there isn't a need to save the registers. This
change is needed by a subsequent patch that will reserve a DMA memory to
save the register contents. The DMA memory region isn't available until
arch initcall and the kernel thermal module could hotplug a core for
thermal considerations.

CRs-fixed: 489391
Change-Id: Idf6ec5212482ccff91500edc4988516389189627
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>