ide: Increase WAIT_DRQ to accomodate some CF cards and SSD drives.

Based upon a patch by Philippe De Muyter, and feedback from Mark
Lord and Robert Hancock.

As noted by Mark Lord, the outdated ATA1 spec specifies a 20msec
timeout for setting DRQ but lots of common devices overshoot this.

Signed-off-by: David S. Miller <davem@davemloft.net>