drivers/dma/ioat: Use the ccflag-y instead of EXTRA_CFLAGS

Changed Makefile to use <modules>-y instead of <modules>-objs. Following
(documentation/kbuild/makefiles.txt).

Signed-off-by: Tracey Dent <tdent48227@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>