hppb: Add missing dma-mapping.h include

This fixes the following build-error:

 CC      drivers/parisc/hppb.o
drivers/parisc/hppb.c: In function ‘hppb_probe’:
drivers/parisc/hppb.c:73: error: implicit declaration of function ‘ccio_request_resource’

Signed-off-by: Frank Lichtenheld <frank@lichtenheld.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>