ide-floppy: merge callbacks

The appropriate functionality of the callback is established through querying
the ATAPI packet command in pc->c[0].

While at it, simplify if (floppy->failed_pc)-branch to be found in the original
idefloppy_request_sense_callback().

Bart:
- keep handling for blk_pc_request() requests unchanged + add FIXME
- add uptodate variable + leave just one idefloppy_end_request() call
- add newline to the debug message

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