IO_DATA_PATH_WIDTH_8 is 0, so a bit-and with it is always false.  The
value IO_DATA_PATH_WIDTH covers the bits of the IO_DATA_PATH constants, so
first pick those bits and then make the test using !=.

This problem was found using Coccinelle (http://coccinelle.lip6.fr/).
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>