IDE: - make ide_inb () and ide_outb () "weak", so boards can

          define there own I/O functions.
          (Needed for the pcs440ep board).
        - The default I/O Functions are again 8 Bit accesses.
        - Added CONFIG_CMD_IDE for the pcs440ep Board.

Signed-off-by: Heiko Schocher <hs@denx.de>