msm:pm: Fix for race condition of starting cpu1 when cpu0 in PC.

There is a window where core sends ipi to secondary core and
wait for it to come online for 1 second. This would allow
core0 to go power collapse in a rare condition where core1
started booting and doesn't become online yet.

Fix this by not allowing power collapse on core0
if hot plug operation is in progress.

CRs-fixed: 545714.
Change-Id: I1ca503a2f09cd9a65c2fdcd41eb54466a1e486c5
Signed-off-by: Anil kumar mamidala <amami@codeaurora.org>