sfc: fix TX channel offset when using legacy interrupts
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 f232af4295653afa4ade3230462b3be15ad16419, it was introduced in version v5.19 by commit c308dfd1b43ef0d4c3e57b741bb3462eb7a7f4a2. For more details please see the references link.