Fix code warning.

Change-Id: Ib11fb49f528d3688351ae349d5b4e307c28b3967
diff --git a/mbtk/test/others/partition_write_demo.c b/mbtk/test/others/partition_write_demo.c
index 1256d75..5edfa2d 100755
--- a/mbtk/test/others/partition_write_demo.c
+++ b/mbtk/test/others/partition_write_demo.c
@@ -3,6 +3,7 @@
 #include <fcntl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 int main(int argc, char *argv[])
 {
@@ -20,11 +21,11 @@
 
     while((len = write(fd, buffer, sizeof(buffer))) > 0){
         count += len;
-        printf("write : %d\n", count);
+        printf("write : %ld\n", count);
         //usleep(1000);
     }
 
-    printf("Write complete,len = %d, errno = %d\n", len, errno);
+    printf("Write complete,len = %ld, errno = %d\n", len, errno);
 
     close(fd);
 #else