libmisc/rtems-fdt: close() file 'bf'

close() file 'bf' to avoid leaking descriptor.

CID 1437645: Resource leak in rtems_fdt_load().

Closes #4297

cpukit/libmisc/rtems-fdt/rtems-fdt.c

@@ -611,6 +611,7 @@ rtems_fdt_load (const char* filename, rtems_fdt_handle* handle)
     return fe;
   }
 
+  close (bf);
   return 0;
 }