geodevga: Add configuration option for output modes

Geode GX2 and LX are supporting Flat Panels. Add new
configuration options to support different output modes.
You can choose between:
* CRT
* Flat Panel
* CRT and Flat Panel

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
diff --git a/vgasrc/Kconfig b/vgasrc/Kconfig
index 6b22c39..089a447 100644
--- a/vgasrc/Kconfig
+++ b/vgasrc/Kconfig
@@ -43,6 +43,27 @@
                 Build support for Geode LX vga.
     endchoice
 
+    choice
+        depends on VGA_GEODEGX2 || VGA_GEODELX
+        prompt "Output Mode"
+        default VGA_OUTPUT_CRT
+
+        config VGA_OUTPUT_CRT
+            bool "CRT"
+            help
+                Use CRT for output.
+
+        config VGA_OUTPUT_PANEL
+            bool "Flat Panel"
+            help
+                Use flat panel for output.
+
+        config VGA_OUTPUT_CRT_PANEL
+            bool "CRT and Flat Panel"
+            help
+                Use CRT and flat panel for output.
+    endchoice
+
     config BUILD_VGABIOS
         bool
         default !NO_VGABIOS