linux-imx

clocksource/drivers/h8300_timer8: Separate the Kconfig option from the arch

The current Kconfig option is the H8300 arch option. In order to comply to the
current rule, let's create a specific option for the timer8 and select it
from the arch's Kconfig.

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