perf/arm-cmn: Drop compile-test restriction

perf/arm-cmn: Drop compile-test restriction

Although CMN is currently (and overwhelmingly likely to remain) deployed
in arm64-only (modulo userspace) systems, the 64-bit "dependency" for
compile-testing was just laziness due to heavy reliance on readq/writeq
accessors. Since we only need one extra include for robustness in that
regard, let's pull that in, widen the compile-test coverage, and fix up
the smattering of type laziness that that brings to light.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/baee9ee0d0bdad8aaeb70f5a4b98d8fd4b1f5786.1638530442.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>