drivers: CCI: add ARM CCI PMU support

Extend the existing CCI driver to support the PMU by registering a perf
backend for it.

Change-Id: I7749907b0b781676885905a569695b207c68cb91
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Dave Martin <dave.martin@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
[will: removed broken __init annotations]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Git-commit: b91c8f284acc2cb2aa43a1ce58322573ad983a14
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Neil Leeder <nleeder@codeaurora.org>