FROMGIT: KVM: arm64: Use symbolic names for the PMU versions

Instead of using a bunch of magic numbers, use the existing definitions
that have been added since 8673e02e ("arm64: perf: Add support
for ARMv8.5-PMU 64-bit counters")

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
(cherry picked from commit 8e26d11f
 git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git

 next)
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I13e35e71ec8620676f3f946925093ec451d6e861
Bug: 178098380
Test: atest VirtualizationHostTestCases on an EL2-enabled device