Patch from Lennert Buytenhek
  
Several files in this directory directly dereference pointers
to on-chip I/O instead of using ixp_reg_write, making them
susceptible to IXP2400 erratum #66. This changset fixes those.
We do not touch any files that will only be built for IXP2800
systems as the 2800 does not have this issue.
  

Signed-off-by: Lennert Buytenhek
Signed-off-by: Deepak Saxena
Signed-off-by: Russell King