clocksource/drivers/acpi_pm: Convert to pr_* macros

Like it's already done in one place in the driver, convert the rest to use pr_*
macros instead of printk(KERN_LEVEL) calls.

While here, join strings to be one string for one line to make grep on them
easier.

There is no functional change.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/1451310085-113182-1-git-send-email-andriy.shevchenko@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>