arm_pmu: add armpmu_alloc_atomic()

arm_pmu: add armpmu_alloc_atomic()

In ACPI systems, we don't know the makeup of CPUs until we hotplug them
on, and thus have to allocate the PMU datastructures at hotplug time.
Thus, we must use GFP_ATOMIC allocations.

Let's add an armpmu_alloc_atomic() that we can use in this case.

Signed-off-by: Mark Rutland <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Will Deacon <[email protected]>