qlogic: check kstrtoul() for errors

We accidentally left out the error handling for kstrtoul().

Fixes: a520030e326a ("qlcnic: Implement flash sysfs callback for 83xx adapter")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed