Meta: Don't override SERENITY_QEMU_DISPLAY_DEVICE if it is already set

Author: https://github.com/rallias 🔰
Commit: 3758dffd16
Pull-request: https://github.com/SerenityOS/serenity/pull/12246

Meta/run.sh

@@ -183,6 +183,7 @@ else
     SERENITY_QEMU_DISPLAY_BACKEND="${SERENITY_QEMU_DISPLAY_BACKEND:-gtk,gl=off}"
 fi
 
+if [ -z "$SERENITY_QEMU_DISPLAY_DEVICE" ]; then
     if [ "$SERENITY_SCREENS" -gt 1 ]; then
         SERENITY_QEMU_DISPLAY_DEVICE="virtio-vga,max_outputs=$SERENITY_SCREENS "
         # QEMU appears to always relay absolute mouse coordinates relative to the screen that the mouse is
@@ -192,6 +193,7 @@ if [ "$SERENITY_SCREENS" -gt 1 ]; then
     else
         SERENITY_QEMU_DISPLAY_DEVICE="VGA,vgamem_mb=64 "
     fi
+fi
 
 # Check if SERENITY_NVME_ENABLE is unset
 if [ -z ${SERENITY_NVME_ENABLE+x} ]; then