ide: allow device drivers to specify per-device type /proc settings

Turn ide_driver_t's 'proc' field into ->proc_entries method
(and also 'settings' field into ->proc_devsets method).  Then
update all device drivers accordingly.

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>