staging: unisys: include: fix improper use of dma_data_direction

Replace use of standard Linux dma_data_direction with a Unisys-
specific uis_dma_data_direction and provide a function to convert
from the latter to the former.  This is necessary because Unisys
s-Par depends on the exact format of this field in multiple OSs
and languages, and so using the standard version creates an
unnecessary dependency between the kernel and s-Par.

Signed-off-by: Steven Matthews <steven.matthews@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: Tim Sell <timothy.sell@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>