Hotplug poweron is not working for boot CPU as it's being
triggerred using PMC and not with Flow Controller. This is
happening because "cpu_powergate_mask" is only getting set
for non-boot CPU's as the boot CPU's first bootup follows
different code path. The patch is marking a CPU as ON within
"cpu_powergate_mask" when turning its power domain on
during power on. This will ensure only first bootup on all
CPU's is using PMC and subsequent hotplug poweron will be
using Flow Controller.

Change-Id: Ie9e86e6f9a777d41508a93d2ce286f31307932c2
Signed-off-by: sumitg <sumitg@nvidia.com>