[ReleasePR postgresql] Fixes to 2022-03-08-preview for PostgreSQL flexible server (#2634)

Create to sync Azure/azure-rest-api-specs#21234
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...azure-sdk:sdkAuto/postgresql?expand=1)

Author: msftbot[bot]

schemas/2022-03-08-preview/Microsoft.DBforPostgreSQL.json

@@ -75,7 +75,7 @@
         "sku": {
           "oneOf": [
             {
-              "$ref": "#/definitions/PostgreSqlSku"
+              "$ref": "#/definitions/Sku"
             },
             {
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
@@ -777,36 +777,6 @@
       },
       "description": "Network properties of a server"
     },
-    "PostgreSqlSku": {
-      "type": "object",
-      "properties": {
-        "name": {
-          "type": "string",
-          "description": "The name of the sku, typically, tier + family + cores, e.g. Standard_D4s_v3."
-        },
-        "tier": {
-          "oneOf": [
-            {
-              "type": "string",
-              "enum": [
-                "Burstable",
-                "GeneralPurpose",
-                "MemoryOptimized"
-              ]
-            },
-            {
-              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
-            }
-          ],
-          "description": "The tier of the particular SKU, e.g. Burstable."
-        }
-      },
-      "required": [
-        "name",
-        "tier"
-      ],
-      "description": "Sku information related properties of a server."
-    },
     "ServerProperties": {
       "type": "object",
       "properties": {
@@ -980,6 +950,36 @@
       },
       "description": "The properties of a server."
     },
+    "Sku": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "type": "string",
+          "description": "The name of the sku, typically, tier + family + cores, e.g. Standard_D4s_v3."
+        },
+        "tier": {
+          "oneOf": [
+            {
+              "type": "string",
+              "enum": [
+                "Burstable",
+                "GeneralPurpose",
+                "MemoryOptimized"
+              ]
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The tier of the particular SKU, e.g. Burstable."
+        }
+      },
+      "required": [
+        "name",
+        "tier"
+      ],
+      "description": "Sku information related properties of a server."
+    },
     "Storage": {
       "type": "object",
       "properties": {