ata: pata_parport-bpck6: remove struct ppc_storage

Store the remaining two variables (cur_ctrl and ppc_flags) in struct
ppc_storage directly in pi->private and remove struct ppc_storage.

Signed-off-by: Ondrej Zary <linux@zary.sk>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>