ide: add CONFIG_IDE_H8300 config option

Add a separate config option for ide-8300 host driver instead of depending
on CONFIG_H8300.

This change is a preparation for the future changes and also allows ide-h8300
to be disabled if needed.

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