ide-disk: factor out generic disk handling code to ide-gd.c

ide-disk: factor out generic disk handling code to ide-gd.c

While at it:
- IDEDISK_VERSION -> IDE_GD_VERSION
- ide_cacheflush_p() -> ide_disk_flush()
- init_idedisk_capacity() -> ide_disk_init_capacity()
- idedisk_set_doorlock() -> ide_disk_set_doorlock()
- idedisk_setup() -> ide_disk_setup()

- ide_disk_capacity() -> ide_gd_capacity()
- ide_disk_remove() -> ide_gd_remove()
- ide_disk_probe() -> ide_gd_probe()
- ide_disk_resume() -> ide_gd_resume()
- ide_device_shutdown() -> ide_gd_shutdown()
- idedisk_driver -> ide_gd_driver
- idedisk_open() -> ide_gd_open()
- idedisk_release() -> ide_gd_release()
- idedisk_getgeo() -> ide_gd_getgeo()
- idedisk_media_changed() -> ide_gd_media_changed()
- idedisk_revalidate_disk() -> ide_gd_revalidate_disk()
- idedisk_ops -> ide_gd_ops
- idedisk_init() -> ide_gd_init()
- idedisk_exit() -> ide_gd_exit()

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>