System76PayloadPkg: Clear screen on boot error

Signed-off-by: Tim Crawford <tcrawford@system76.com>

Author: crawfxrd

System76PayloadPkg/Library/PlatformBootManagerLib/PlatformBootManager.c

@@ -198,6 +198,9 @@ PlatformBootManagerUnableToBoot (
   // here to see if it makes sense to request and wait for a keypress.
   //
   if (gST->ConIn != NULL) {
+    if (gST->ConOut != NULL) {
+      gST->ConOut->ClearScreen (gST->ConOut);
+    }
     AsciiPrint (
       "%a: No bootable option or device was found.\n"
       "%a: Press any key to enter the Boot Manager Menu.\n",