Add GNSS N50DB support.

Change-Id: Id65a69a0a7c149ef1e75db01e544f94b4f178d45
diff --git a/mbtk/mbtk_gnssd/gnss_info.h b/mbtk/mbtk_gnssd/gnss_info.h
index 744aba5..34aa6b1 100755
--- a/mbtk/mbtk_gnssd/gnss_info.h
+++ b/mbtk/mbtk_gnssd/gnss_info.h
@@ -14,6 +14,7 @@
 #define GNSS_ID_6228 "6228"
 #define GNSS_ID_5311 "5311"
 #define GNSS_ID_8122 "8122"
+#define GNSS_ID_N50DB "N50DB"
 
 #define GNSS_PRINT_PORT_UART1       1           // 1
 #define GNSS_PRINT_PORT_USB_NMEA    (1<<1)      // 2
@@ -72,7 +73,8 @@
 typedef enum {
     GNSS_TYPE_6228 = 0,
     GNSS_TYPE_5311,
-    GNSS_TYPE_8122
+    GNSS_TYPE_8122,
+    GNSS_TYPE_N50DB
 } gnss_id_enum;
 
 typedef enum {