* disk/ata.c (grub_ata_pio_read): Don't wait for the command to
become activate.
(grub_ata_pio_write): Likewise.
(grub_atapi_identify): Wait after issuing an ATA command.
(grub_atapi_packet): Likewise.
(grub_ata_identify): Likewise.
(grub_ata_readwrite): Likewise.