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

BugLink: https://bugs.launchpad.net/bugs/1868629

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: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

arch/arm/kernel/vdso.c

@@ -84,6 +84,8 @@ static bool __init cntvct_functional(void)
 	 * this.
 	 */
 	np = of_find_compatible_node(NULL, NULL, "arm,armv7-timer");
+	if (!np)
+		np = of_find_compatible_node(NULL, NULL, "arm,armv8-timer");
 	if (!np)
 		goto out_put;