In brief: Considering that AMD has already launched most, if not all, Radeon RX 6000 series cards, it's weird to see the company adding 17 new PCI IDs of RDNA2 GPUs to its open-source Linux graphics drivers. However, that's what happened, suggesting that we might be in for a Navi 2x GPUs refresh.
Before getting your hopes up, the new 17 PCI IDs found in the AMDGPU Linux driver may not be directly linked to 17 new AMD GPUs, as PCI IDs are also used for engineering samples and custom-designed models from the AIB partners.
To better understand the PCI ID list, it's worth remembering Sienna Cichlid is the codename for the Navi 21, Navy Flounder for the Navi 22, and Dimgrey Cavefish for the Navi 23. The new PCI IDs in the patch notes can be identified by the "+" sign before the entry.
Out of the 17 new entries, 5 are Sienna Cichlid: (0x73A5, 0x73A8, 0x73A9, 0x73AC, 0x73AD). In the Navy Flounder segment of the list, there are another 5: 0x73DA, 0x73DB, 0x73DC, 0x73DD, and 0x73DE. The remaining 7, which are 0x73E8, 0x73E9, 0x73EA, 0x73EB, 0x73EC, 0x73ED, and 0x73EF, are Dimgrey Cavefish.
Rumors about a possible refresh of the Navi 2x GPUs have come and gone for a while. Previous reports claimed that the refresh SKUs would be based on the 6nm process node, offering better performance and efficiency than the current-gen cards.
These refreshed GPUs could either be an entirely new lineup of graphics cards or part of the Radeon RX 7000 series lineup, which is expected to feature refreshed Navi 2x GPUs and the new Navi 3x GPUs.
Besides AMD, Nvidia is also possibly refreshing the RTX 30 series by launching the Super variants. Rumors about the RTX 3090 Super SKU have emerged recently, stating the card would feature a fully-enabled GA102 GPU with 10,752 CUDA cores, 21GBps GDDR6X memory, and a TGP of 450W or more. This card is expected to launch later this year.