[MLIR][CODEOWNERS] Add XeGPU transform ops code owners (#168940)

Add charithaintc, Jianhui-Li and tkarna as code owners of XeGPU/TransformOps directories.

Author: tkarna

.github/CODEOWNERS

@@ -71,6 +71,8 @@
 /mlir/lib/Conversion/*XeGPU* @charithaintc @Jianhui-Li
 /mlir/include/mlir/Dialect/XeGPU/Transforms @charithaintc @Jianhui-Li
 /mlir/lib/Dialect/XeGPU/Transforms @charithaintc @Jianhui-Li
+/mlir/include/mlir/Dialect/XeGPU/TransformOps @charithaintc @Jianhui-Li @tkarna
+/mlir/lib/Dialect/XeGPU/TransformOps @charithaintc @Jianhui-Li @tkarna
 /mlir/include/mlir/Dialect/LLVMIR/XeVM* @silee2
 /mlir/lib/Dialect/LLVMIR/IR/XeVM @silee2
 /mlir/lib/Conversion/*XeVM* @silee2