add new api for mbtk,get modem version

Change-Id: I8cebf6552ee47eef2c8d2e980a0d6436c9a55ef8
diff --git a/mbtk/libmbtk_lib/ril/mbtk_info.c b/mbtk/libmbtk_lib/ril/mbtk_info.c
index b61a3b0..58358ca 100755
--- a/mbtk/libmbtk_lib/ril/mbtk_info.c
+++ b/mbtk/libmbtk_lib/ril/mbtk_info.c
@@ -213,6 +213,9 @@
         case MBTK_INFO_ID_DEV_VERSION_REQ:
         case MBTK_INFO_ID_DEV_VERSION_RSP:
             return "VERSION";
+        case MBTK_INFO_ID_DEV_MD_VERSION_REQ:
+        case MBTK_INFO_ID_DEV_MD_VERSION_RSP:
+            return "MD_VERSION";
         case MBTK_INFO_ID_DEV_MODEL_REQ:
         case MBTK_INFO_ID_DEV_MODEL_RSP:
             return "MODEL";