ide: add IDE_HFLAG_ERROR_STOPS_FIFO host flag

Add IDE_HFLAG_ERROR_STOPS_FIFO host flag and use it instead
of hwif->err_stops_fifo.  As a side-effect this change fixes
hwif->err_stops_fifo not being restored by ide_hwif_restore().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>