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: NJames Lentini <jlentini@netapp.com>
Signed-off-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>