radeon: add new SI pci id

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
diff --git a/radeon/r600_pci_ids.h b/radeon/r600_pci_ids.h
index b9a85db..3b67cbe 100644
--- a/radeon/r600_pci_ids.h
+++ b/radeon/r600_pci_ids.h
@@ -323,6 +323,7 @@
 CHIPSET(0x6798, TAHITI_6798, TAHITI)
 CHIPSET(0x6799, TAHITI_6799, TAHITI)
 CHIPSET(0x679A, TAHITI_679A, TAHITI)
+CHIPSET(0x679B, TAHITI_679B, TAHITI)
 CHIPSET(0x679E, TAHITI_679E, TAHITI)
 CHIPSET(0x679F, TAHITI_679F, TAHITI)