Remove unnecessary deprecation annotation

Private members on private companion objects have proper visibility
so there is no need for the @Deprecated annotation.

^KT-54539 Fixed

compiler/testData/codegen/bytecodeListing/privateCompanionFields.kt

@@ -16,6 +16,15 @@ class TestClass {
     }
 }
 
+class TestClass2 {
+
+    private companion object {
+        val testPublic: String = "1"
+        private val testPrivate: String = "2"
+        const val testPublicConst: String = "3"
+    }
+}
+
 interface TestConst {
 
     private companion object {
@@ -29,4 +38,4 @@ interface TestJvmField {
         @JvmField
         val test3: String = "3"
     }
-}
+}