GSD-2022-1000805 net/smc: Use a mutex for locking "struct smc_pnettable"

net/smc: Use a mutex for locking "struct smcpnettable" This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.15.26 by commit...