Add GNSS N50DB support.

Change-Id: Id65a69a0a7c149ef1e75db01e544f94b4f178d45
diff --git a/mbtk/mbtk_gnssd/gnss_n50db.h b/mbtk/mbtk_gnssd/gnss_n50db.h
new file mode 100755
index 0000000..41267c4
--- /dev/null
+++ b/mbtk/mbtk_gnssd/gnss_n50db.h
@@ -0,0 +1,30 @@
+/*
+* gnss_n50db.h
+*
+* MBTK N50-DB GNSS support header file.
+*
+* Author : lb
+* Date   : 2024/7/18 11:28:32
+*/
+#ifndef __GNSS_N50DB_H
+#define __GNSS_N50DB_H
+#include "gnss_info.h"
+#include "mbtk_type.h"
+
+
+int gnss_n50db_dev_open();
+
+int gnss_n50db_dev_close(int fd);
+
+int gnss_n50db_open(const char *dev);
+
+int gnss_n50db_close(int fd);
+
+int gnss_n50db_fw_dl(int fd, const char *fw_name, const char *dev);
+
+void gnss_n50db_set_cb(const void *data, int data_len);
+
+gnss_err_enum gnss_n50db_set(int fd, const char *cmd, void *cmd_rsp, int cmd_rsp_len);
+
+
+#endif /* __GNSS_N50DB_H */