ide: remove task_ioreg_t typedef (take 2)

Remove task_ioreg_t typedef from the kernel code (but leave it
in <linux/hdreg.h> for #ifndef/#endif __KERNEL__ case).

While at it also move sata_ioreg_t typedef under #ifndef/#endif __KERNEL__.

v2:
Remove name of the second parameter from ide_execute_command() declaration.
(Noticed by Sergei).

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>