IB/mad: Remove unused includes

The ib_mad module does not use a kthread function, but mad_priv.h
includes <linux/kthread.h>.  mad_rmpp.c does not do any DMA-related
stuff, but includes <linux/dma-mapping.h>.  Remove the unused includes.
Signed-off-by: James Lentini <jlentini@netapp.com>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/mad_priv.h

@@ -39,7 +39,6 @@
 
 #include <linux/completion.h>
 #include <linux/pci.h>
-#include <linux/kthread.h>
 #include <linux/workqueue.h>
 #include <rdma/ib_mad.h>
 #include <rdma/ib_smi.h>

drivers/infiniband/core/mad_rmpp.c

@@ -33,8 +33,6 @@
  * $Id: mad_rmpp.c 1921 2005-03-02 22:58:44Z sean.hefty $
  */
 
-#include <linux/dma-mapping.h>
-
 #include "mad_priv.h"
 #include "mad_rmpp.h"