Update README.md

Author: liuguo09

README.md

@@ -35,4 +35,4 @@
 | tissot-n-oss | Mi A1 | Android N | LA.UM.5.3-06310-89xx.0 | [tissot-n-oss](https://github.com/MiCode/Xiaomi_Kernel_OpenSource/tree/tissot-n-oss) |
 | tissot-o-oss | Mi A1 | Android O | LA.UM.6.6.r1-04000-89xx.0 | [tissot-o-oss](https://github.com/MiCode/Xiaomi_Kernel_OpenSource/tree/tissot-o-oss) |
 | whyred-n-oss | Redmi Note 5 | Android N | LA.UM.6.1.r1-11000-sdm660.0 | [whyred-n-oss](https://github.com/MiCode/Xiaomi_Kernel_OpenSource/tree/whyred-n-oss) |
-
+| polaris-o-oss | MIX 2S | Android O | LA.UM.6.3.r1_r00455 | [polaris-o-oss](https://github.com/MiCode/Xiaomi_Kernel_OpenSource/tree/polaris-o-oss) |