arm64: topology: Implement basic CPU topology support

Add basic CPU topology support to arm64, based on the existing pre-v8
code and some work done by Mark Hambleton.  This patch does not
implement any topology discovery support since that should be based on
information from firmware, it merely implements the scaffolding for
integration of topology support in the architecture.

No locking of the topology data is done since it is only modified during
CPU bringup with external serialisation from the SMP code.

The goal is to separate the architecture hookup for providing topology
information from the DT parsing in order to ease review and avoid
blocking the architecture code (which will be built on by other work)
with the DT code review by providing something simple and basic.

Following patches will implement support for interpreting topology
information from MPIDR and for parsing the DT topology bindings for ARM,
similar patches will be needed for ACPI.

Change-Id: Ie8a6e608ff8d42b205a40c41ff6dd87d2f2af6b3
Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
[catalin.marinas@arm.com: removed CONFIG_CPU_TOPOLOGY, always on if SMP]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: f6e763b93a6cd3411fd8df925344022719bcba62
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[rvaswani@codeaurora.org: resolved minor merge conflict in Makefile]
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>