ide-floppy: use an xfer_func_t and io_buf_t typedefs in order to unify rw

Also, move xfer_func_t typedef to the ide.h since it is used by two drivers
now (more coming).

Bart:
- use __func__ while at it

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

include/linux/ide.h

@@ -627,6 +627,9 @@ typedef struct hwif_s {
 typedef ide_startstop_t (ide_handler_t)(ide_drive_t *);
 typedef int (ide_expiry_t)(ide_drive_t *);
 
+/* used by ide-cd, ide-floppy, etc. */
+typedef void (xfer_func_t)(ide_drive_t *, void *, u32);
+
 typedef struct hwgroup_s {
 		/* irq handler, if active */
 	ide_startstop_t	(*handler)(ide_drive_t *);