configurations: santabarbara: fix MB VR sensor name conflict

MB_VR2916 ADC sensor shared the same name "MB_PVDD18_S5_VOLT_V" with
another ADC sensor.
Rename this VR sensor to "MB_VR_PVDD18_S5_VOLT_V" to avoid the name
conflict.

Test on santabarbara platform
```
root@bmc:~# busctl tree xyz.openbmc_project.PSUSensor | grep MB_VR_PVDD18
        ├─ /xyz/openbmc_project/sensors/voltage/MB_VR_PVDD18_S5_VOLT_V
```

Change-Id: I82cffbc34d9dcfbb2c4e0051d06c0a084fdf8d52
Signed-off-by: Henry Wu <Henry_Wu@quantatw.com>
diff --git a/configurations/meta/santabarbara/santabarbara_mb.json b/configurations/meta/santabarbara/santabarbara_mb.json
index 9d90c2d..e4b0092 100644
--- a/configurations/meta/santabarbara/santabarbara_mb.json
+++ b/configurations/meta/santabarbara/santabarbara_mb.json
@@ -966,7 +966,7 @@
             "iout1_Name": "MB_VR_CPU_PVDDCR_CPU1_CURR_A",
             "pout1_Name": "MB_VR_CPU_PVDDCR_CPU1_PWR_W",
             "vout1_Name": "MB_VR_CPU_PVDDCR_CPU1_VOLT_V",
-            "vout2_Name": "MB_PVDD18_S5_VOLT_V"
+            "vout2_Name": "MB_VR_PVDD18_S5_VOLT_V"
         },
         {
             "Address": "0x4d",