sfc/siena: fix null pointer dereference in efxhardstart_xmit
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 v6.0 by commit 589c6eded10c77a12b7b2cf235b6b19a2bdb91fa, it was introduced in version v5.10 by commit 12804793b17c0e19115a90d98f2f3df0cb79e233. For more details please see the references link.