perf print-events: Export is_event_supported()

perf print-events: Export is_event_supported()

Will be used when checking if we can encode the PMU number in
perf_event_attr.type, part of the logic to use in hybrid systems
(multiple types of CPUs, such as Intel's (Alder Lake, etc) or ARM's
big.LITTLE).

Co-developed-with: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/linux-perf-users/ZIzYgImv61OGK1wA@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>