ide: prepare for merging ide-gd-floppy.c with ide-gd.c

- idefloppy_ref_mutex -> ide_disk_ref_mutex
- idefloppy_cleanup_obj() -> ide_disk_release()
- ide_floppy_get() -> ide_disk_get()
- ide_floppy_put() -> ide_disk_put()
- ide_floppy_capacity() -> ide_gd_capacity()
- ide_floppy_remove() -> ide_gd_remove()
- ide_floppy_probe() -> ide_gd_probe()
- idefloppy_driver -> ide_gd_driver
- idefloppy_open() -> ide_gd_open()
- idefloppy_release() -> ide_gd_release()
- idefloppy_getgeo() -> ide_gd_getgeo()
- idefloppy_media_changed() -> ide_gd_media_changed()
- idefloppy_revalidate_disk() -> ide_gd_revalidate_disk()
- idefloppy_ops -> ide_gd_ops
- idefloppy_init() -> ide_gd_init()
- idefloppy_exit() -> ide_gd_exit()

- 'floppy' -> 'idkp' in ide_disk_*() and ide_gd_*()
- idefloppy_floppy_t -> struct ide_floppy_obj

There should be no functional changes caused by this patch.

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