Add legacy fast HDMI boards to GNOME and XFCE desktop targets

- Include legacy branch fast HDMI boards in GNOME desktop builds
- Add new XFCE desktop target specifically for legacy fast HDMI boards
- Treat legacy fast HDMI similar to vendor fast HDMI for desktop images

Signed-off-by: Igor Pecovnik <igor@armbian.com>

Author: igorpecovnik

scripts/generate_targets.py

@@ -843,7 +843,7 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
             yaml += '      - *stable-vendor-slow-hdmi\n'
 
     # Ubuntu stable GNOME desktop (fast HDMI only)
-    if current_fast:
+    if current_fast or legacy_fast:
         yaml += """
   # Ubuntu stable GNOME desktop (fast HDMI only)
   desktop-stable-ubuntu-gnome:
@@ -860,10 +860,13 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
       DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
       DESKTOP_APPGROUPS_SELECTED: "programming"
     items:
-      - *stable-current-fast-hdmi
 """
+        if current_fast:
+            yaml += '      - *stable-current-fast-hdmi\n'
         if vendor_fast:
             yaml += '      - *stable-vendor-fast-hdmi\n'
+        if legacy_fast:
+            yaml += '      - *stable-legacy-fast-hdmi\n'
 
     # Ubuntu stable KDE Neon desktop (fast HDMI only)
     if current_fast:
@@ -888,6 +891,27 @@ def generate_stable_yaml(conf_wip_boards, manual_content=""):
         if vendor_fast:
             yaml += '      - *stable-vendor-fast-hdmi\n'
 
+    # Ubuntu stable XFCE desktop for legacy fast HDMI boards
+    if legacy_fast:
+        yaml += """
+  # Ubuntu stable XFCE desktop for legacy fast HDMI boards
+  desktop-stable-ubuntu-legacy-xfce:
+    enabled: yes
+    configs: [ armbian-images ]
+    pipeline:
+      gha: *armbian-gha
+    build-image: "yes"
+    vars:
+      RELEASE: noble
+      BUILD_MINIMAL: "no"
+      BUILD_DESKTOP: "yes"
+      DESKTOP_ENVIRONMENT: "xfce"
+      DESKTOP_ENVIRONMENT_CONFIG_NAME: "config_base"
+      DESKTOP_APPGROUPS_SELECTED: "programming"
+    items:
+      - *stable-legacy-fast-hdmi
+"""
+
     # Ubuntu stable XFCE desktop for RISC-V boards
     if current_riscv64 or vendor_riscv64:
         yaml += """