clocksource/drivers/arm_arch_timer: Remove unneeded pr_fmt macro

After this commit ded24019(clocksource: arm_arch_timer: clean up
printk usage), the previous macro is redundant, so delete it.

And move the new macro to the previous position.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>