ide: do not access ide_drive_t 'drive_data' field directly

Change ide_drive_t 'drive_data' field from 'unsigned int' type to 'void *'
type, allowing a wider range of values/types to be stored in this field.

Added 'ide_get_drivedata' and 'ide_set_drivedata' helpers to get and set
the 'drive_data' field.

Fixed all host drivers to maintain coherency with the change in the
'drive_data' field type.

Signed-off-by: Joao Ramos <joao.ramos@inov.pt>
[bart: fix qd65xx build, cast to 'unsigned long', minor Coding Style fixups]
Acked-by: Sergei Shtylyov <sshtylyov@ru.montavista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>