ata: pata_parport-bpck6: remove PPC_FLAGS

pi->private is now not used for any other purpose, so store wait_fifo
flag directly there and remove PPC_FLAGS define.

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>