McuSupport: Skip Renesas' "RGL" board SDK

ghs-renesas-rh850-d1m1a.json lists "boardSdk/envVar": "RGL_DIR".
However, that dependency is already handled as vendorSdk. This and the
other board SDKs differ so much, that we simply keep "RGL" as vendorSdk
and skip it when creating board SDKs.

Amends c43ef81d4f

Task-number: QTCREATORBUG-24201
Change-Id: I052d50f413ecc5f318d4146c207ab690acf1b1f5
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/mcusupport/mcusupportsdk.cpp

@@ -280,7 +280,8 @@ static QVector<McuTarget *> targetsFromDescriptions(const QList<McuTargetDescrip
                 QVector<McuPackage*> required3rdPartyPkgs = {
                     vendorPkgs.value(desc.platformVendor), tcPkg
                 };
-                if (!desc.boardSdkEnvVar.isEmpty()) {
+                if (!desc.boardSdkEnvVar.isEmpty()
+                        && desc.boardSdkEnvVar != "RGL_DIR") { // Already included in vendorPkgs
                     if (!boardSdkPkgs.contains(desc.boardSdkEnvVar)) {
                         auto boardSdkPkg = createBoardSdkPackage(desc.boardSdkEnvVar);
                         boardSdkPkgs.insert(desc.boardSdkEnvVar, boardSdkPkg);