fujitsu-laptop: Use module name in debug messages

vdbg_printk() always prefixes the log messages it generates with
"FUJ02B1", which can be misleading, because it might have been called
while handling a notify for ACPI device FUJ02E3 or during module
initialization etc.  Employ pr_fmt() to prefix debug messages with the
module name instead and thus avoid confusion.

Reported-by: Jan-Marek Glogowski <glogow@fbihome.de>
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Acked-by: Jonathan Woithe <jwoithe@just42.net>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>