Fix whitespace, remove pointless volatile qualifiers and improve code style
by use of INPUT_DATA_REG and OUTPUT_DATA_REG macros.
Signed-off-by: NFinn Thain <fthain@telegraphics.com.au>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>