configurations: Fix bus index offset

Adjusted MUX channel-to-bus mapping to ensure accurate access to the
CX8 temperature sensor.

Change-Id: Iad8a631d4a4fa5f4db5fa8bb7958a93062cac7e1
Signed-off-by: Alex Wang <alex.ts.wang@fii-foxconn.com>
diff --git a/configurations/nvidia_gb300_io_board.json b/configurations/nvidia_gb300_io_board.json
index 99bc2b3..0f2b997 100644
--- a/configurations/nvidia_gb300_io_board.json
+++ b/configurations/nvidia_gb300_io_board.json
@@ -8,7 +8,7 @@
         },
         {
             "Address": "0x1f",
-            "Bus": "$bus - 5",
+            "Bus": "$bus + 3",
             "Labels": [
                 "temp2"
             ],
@@ -42,7 +42,7 @@
         },
         {
             "Address": "0x1f",
-            "Bus": "$bus - 3",
+            "Bus": "$bus + 6",
             "Labels": [
                 "temp2"
             ],