clocksource/drivers/arm_arch_timer: Remove any trace of the TVAL programming interface

TVAL usage is now long gone, get rid of the leftovers.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211017124225.3018098-11-maz@kernel.org


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>