ARM: dts: exynos: Add CPU perf counters to Exynos54xx boards

Enable support for ARM Performance Monitoring Units available in Cortex-A7
and Cortex-A15 CPU cores for Exynos54xx SoCs (5410, 5420 and 5422/5800).

The PMUs interrupts are defined in the common exynos54xx.dtsi device tree,
but the PMUs are enabled and have their interrupt CPU affinity defined
next to each SoC's cpus node.

Tested with perf on Odroid XU4 (Exynos5422):
armv7_cortex_a7 PMU driver: 5 counters available
armv7_cortex_a15 PMU driver: 7 counters available

Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Marian Mihailescu <mihailescu2m@gmail.com>
Signed-off-by: Willy Wolff <willy.mh.wolff@gmail.com>
[mszyprow: reordered nodes according to krzk request, fixed typos]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>