Commit 7175f059 ("arm64: perf: Enable PMCR long cycle counter bit")
added initial support for a 64-bit cycle counter enabled using PMCR.LC.

Unfortunately, that patch doesn't extend ARMV8_EVTYPE_MASK, so any
attempts to set the enable bit are ignored by armv8pmu_pmcr_write.

This patch extends the mask to include the new bit.
Signed-off-by: Will Deacon <will.deacon@arm.com>