mmc: Add module.h to drivers/mmc users assuming implicit presence.

We are cleaning up the implicit presence of module.h; these guys are
some of the people who just assume it will be there.  Call it out
explitly for those that really need it.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 7c1e16a..92946b8 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -27,6 +27,7 @@
 #include <linux/sched.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
+#include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/dma-mapping.h>
 #include <linux/crc7.h>