ACPI: scan: Unify the log message printing

The log messages in scan.c is not in consistency, some pr_*() calls
have PREFIX, but some don't.

Using pr_fmt() and remove PREFIX, also replace printk() with pr_*()
macro to unify the message printing.

Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>