drivers/base: dma-coherent.c is a module and needs module.h

It was implicitly getting it before, but it will break compiles
once we fix that.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/base/dma-coherent.c

diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
index f369e27..bb0025c 100644
--- a/drivers/base/dma-coherent.c
+++ b/drivers/base/dma-coherent.c
@@ -4,6 +4,7 @@
  */
 #include <linux/slab.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/dma-mapping.h>
 
 struct dma_coherent_mem {