KVM: arm64: selftests: Add physical timer registers to the sysreg list

Now that KVM exposes CNTPCT_EL0, CNTP_CTL_EL0 and CNT_CVAL_EL0 to
userspace, add them to the get-reg-list selftest.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-19-maz@kernel.org