Staging: gdm72xx: make "len" unsigned

We had an underflow bug here and I think I fixed it but we may as
well be proactive and make "len" unsigned to be double sure.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
4 files changed