ARM: 8957/1: VDSO: Match ARMv8 timer in cntvct_functional()

BugLink: https://bugs.launchpad.net/bugs/1868538



commit 45939ce2 upstream.

It is possible for a system with an ARMv8 timer to run a 32-bit kernel.
When this happens we will unconditionally have the vDSO code remove the
__vdso_gettimeofday and __vdso_clock_gettime symbols because
cntvct_functional() returns false since it does not match that
compatibility string.

Fixes: ecf99a43 ("ARM: 8331/1: VDSO initialization, mapping, and synchronization")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>