fix(mmc): resolve the build error

Adding the header file plat/common/common_def.h to
resolve the "SIZE_128" undeclared identifier error.

Change-Id: I399edf4248776f6dd9f93e000b8672cadc71509d
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 51e94be..8e83464 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -16,6 +16,7 @@
 #include <drivers/delay_timer.h>
 #include <drivers/mmc.h>
 #include <lib/utils.h>
+#include <plat/common/common_def.h>
 
 #define MMC_DEFAULT_MAX_RETRIES		5
 #define SEND_OP_COND_MAX_RETRIES	100