arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled

arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled

BugLink: https://bugs.launchpad.net/bugs/1713821
Userspace being allowed to use read CNTVCT_EL0 anytime (and not
only in the VDSO), we need to enable trapping whenever a cntvct
workaround is enabled on a given CPU.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
(cherry picked from commit a86bd139f2ae02f960caeb0c1dd5f871d3e087cd)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>