[gbinder] Explicitly ignore return value. JB#61912

Recognized by Coverity (CID 444485) that this is the single call to
gbinder_driver_write out of the total of 9, where the return value is
not checked.

This change is implemented just to make Coverity happy.  The compiler
does not complain.

src/gbinder_driver.c

@@ -1173,7 +1173,7 @@ gbinder_driver_free_buffer(
         write.ptr = (uintptr_t)wbuf;
         write.size = len;
         write.consumed = 0;
-        gbinder_driver_write(self, &write);
+        (void) gbinder_driver_write(self, &write);
     }
 }