arm: pmu: Fix overflow checks for PMUv3p5 long counters

PMUv3p5 uses 64-bit counters irrespective of whether the PMU is configured
for overflowing at 32 or 64-bits. The consequence is that tests that check
the counter values after overflowing should not assume that values will be
wrapped around 32-bits: they overflow into the other half of the 64-bit
counters on PMUv3p5.

Fix tests by correctly checking overflowing-counters against the expected
64-bit value.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Andrew Jones <andrew.jones@linux.dev>