octeontx2-af: Block VFs from clobbering special CGX PKIND state

In the Linux kernel, the following vulnerability has been resolved: octeontx2-af: Block VFs from clobbering special CGX PKIND state PF and VF NIX LFs that share a CGX LMAC reuse the same hardware PKIND programming. When HiGig2 or EDSA parsing is enabled, a VF NIX LF alloc must not reset the LMAC RX PKIND or default TX parse config over the PF setup. Add cgx_get_pkind() and rvu_cgx_is_pkind_config_permitted() so VFs skip cgx_set_pkind(), rvu_npc_set_pkind(), and NIX_AF_LFX_TX_PARSE_CFG updates when the LMAC is using NPC_RX_HIGIG_PKIND or NPC_RX_EDSA_PKIND.