ncr5380: Remove duplicate comments

The LIMIT_TRANSFERSIZE, PSEUDO_DMA, PARITY and UNSAFE options are all
documented in the core drivers where they are used. The same goes for the
chip databook reference. Remove the duplicate comments.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>