CVE-2026-72312: octeontx2-af: fix VF bringup affecting PF promiscuous state

In the Linux kernel, the following vulnerability has been resolved:

octeontx2-af: fix VF bringup affecting PF promiscuous state

Mbox handling of nixsetrxmode for a VF with promiscuous and allmulti flags set to false causes deletion of the PF's promiscuous and allmulti MCAM rules. This occurs because the APIs that enable/disable these rules operate only on the PF, even when the mbox request is made via a VF interface.

Guard both rvunpcenableallmultientry() and rvunpcenablepromiscentry() disable paths with an isvf() check so that a VF bringing up or tearing down its interface cannot inadvertently clear the PF's MCAM rules.