cacheinfo: Use atomic allocation for percpu cache attributes

On couple of architectures like RISC-V and ARM64, we need to detect
cache attribues quite early during the boot when the secondary CPUs
start. So we will call detect_cache_attributes in the atomic context
and since use of normal allocation can sleep, we will end up getting
"sleeping in the atomic context" bug splat.

In order avoid that, move the allocation to use atomic version in
preparation to move the actual detection of cache attributes in the
CPU hotplug path which is atomic.

Cc: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>