Fix code warning.

Change-Id: Ib11fb49f528d3688351ae349d5b4e307c28b3967
diff --git a/mbtk/mbtk_gnssd/hd8122_dl/port.c b/mbtk/mbtk_gnssd/hd8122_dl/port.c
index 89e1596..68c32f1 100755
--- a/mbtk/mbtk_gnssd/hd8122_dl/port.c
+++ b/mbtk/mbtk_gnssd/hd8122_dl/port.c
@@ -475,7 +475,7 @@
     return 0;

 }

 

-int OpenUart(char* UART_DEV)

+int OpenUart(const char* UART_DEV)

 {

     int fd=0;