[partition] Always offer a 'no bootloader' item

- this branch is importing parts of a PR from Anubhav, so add
  relevant SPDX tag as well.

src/modules/partition/core/BootLoaderModel.cpp

@@ -3,6 +3,7 @@
  *   SPDX-FileCopyrightText: 2014 Aurélien Gâteau <agateau@kde.org>
  *   SPDX-FileCopyrightText: 2015 Teo Mrnjavac <teo@kde.org>
  *   SPDX-FileCopyrightText: 2019 Adriaan de Groot <groot@kde.org>
+ *   SPDX-FileCopyrightText: 2021 Anubhav Choudhary <ac.10edu@gmail.com>
  *   SPDX-License-Identifier: GPL-3.0-or-later
  *
  *   Calamares is Free Software: see the License-Identifier above.
@@ -79,7 +80,7 @@ BootLoaderModel::updateInternal()
     clear();
     createMbrItems();
 
-    // An empty model is possible if you don't havee permissions: don't crash though.
+    // An empty model is possible if you don't have permissions: don't crash though.
     if ( rowCount() < 1 )
     {
         return;
@@ -124,10 +125,10 @@ BootLoaderModel::updateInternal()
         {
             appendRow( createBootLoaderItem( partitionText, PartitionInfo::mountPoint( partition ), true ) );
         }
-
-        // Create "don't install bootloader" item
-        appendRow( createBootLoaderItem( tr( "Do not install a boot loader" ), QString(), false ) );
     }
+    // Create "don't install bootloader" item. This is always available,
+    // also if there was no /boot or / partition found.
+    appendRow( createBootLoaderItem( tr( "Do not install a boot loader" ), QString(), false ) );
 }