CVE-2024-50259 netdevsim: Add trailing zero to terminate the string in nsim_nexthop_bucket_activity_write()

In the Linux kernel, the following vulnerability has been resolved: netdevsim: Add trailing zero to terminate the string in nsimnexthopbucketactivitywrite This was found by a static analyzer. We should not forget the trailing zero after copyfromuser if we will further do some string operations,...