[PATCH] Remove gratuitous inclusion of <linux/config.h> from <linux/dmaengine.h>

We include config.h on the compiler command line. There's no need for it
to be included again.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>