Staging: pata_rdc: convert code to work in 2.6.29

This fixes build problems in the pata_rdc driver due to api changes in
the libata layer.


Cc: Kevin Huang  <Kevin.Huang@rdc.com.tw>
Cc: Tomy Wang <Tomy.Wang@rdc.com.tw>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>