ARM: sunxi: Add initialization of CNTVOFF

Add the initialization of CNTVOFF for sun8i-a83t.

For boot CPU, create a new machine that handles this
function's call in an "init_early" callback. We need to initialize
CNTVOFF before the arch timer's initialization otherwise, it will
not be taken into account and fails to boot correctly.
Because of that, this function can't be called in SMP's early_initcall
function which is called after timer's init.

For secondary CPUs, add this function into secondary_startup
assembly entry.

Signed-off-by: Mylène Josserand <mylene.josserand@bootlin.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>