ide-floppy: cleanup and unify debugging macro calls

* some debug_log() calls were not using "ide-floppy: " prefix

* a few used printk levels different than KERN_INFO (KERN_NOTICE
  and KERN_ERR, which is the default one if no level is given)

Bart:
- fix build issues for IDEFLOPPY_DEBUG_LOG set to 1 while at it
- s/__FUNCTION__/__func__/

Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>