remove BLK_DEV_HD_ONLY

After commit 80aa31cb


(ide: remove CONFIG_BLK_DEV_HD_IDE config option (take 2))
the indirection through BLK_DEV_HD_ONLY is no longer required.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: rmk@arm.linux.org.uk
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>