sched/hmp: Use GFP_KERNEL for top task memory allocations

Task load structure allocations can consume a lot of memory as the
number of tasks begin to increase. Also they might exhaust the atomic
memory pool pretty quickly if a workload starts spawning lots of
threads in a short amount of time thus increasing the possibility of
failed allocations. Move the call to init_new_task_load() outside
atomic context and start using GFP_KERNEL for allocations. There is
no need for this allocation to be in atomic context.

Change-Id: I357772e10bf8958804d9cd0c78eda27139054b21
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>