clocksource/drivers/fttmr010: Pass around less pointers

Just pass bool flags from the different initcalls and use the
flags to set the right pointers. This results in less pointers
passed around in init.

Cc: Cédric Le Goater <clg@kaod.org>
Cc: Joel Stanley <joel@jms.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210724224424.2085404-1-linus.walleij@linaro.org