staging: kpc2000: prevent underflow in cpld_reconfigure()
This function should not allow negative values of "wr_val". If
negatives are allowed then capping the upper bound at 7 is
meaningless. Let's make it unsigned.
Fixes:
7dc7967fc39a ("staging: kpc2000: add initial set of Daktronics drivers")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200224103325.hrxdnaeqsthplu42@kili.mountain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>