post-image: Remove old QEMU remnants

TODO: Restore x86_64 support

board/common/post-image.sh

@@ -1,16 +1 @@
 #!/bin/sh
-
-# shellcheck disable=SC1090
-. "$BR2_CONFIG" 2>/dev/null
-
-cat <<-EOF >"$BINARIES_DIR/qemu.sh"
-	#!/bin/sh
-	line=\$(stty -g)
-	stty raw
-	qemu-system-x86_64 -M pc -cpu kvm64 -enable-kvm -nographic			\\
-	    -kernel bzImage -append "rootwait root=/dev/vda console=ttyS0 quiet"	\\
-	    -drive file=rootfs.ext2,if=virtio,format=raw				\\
-	    -net nic,model=virtio -net user
-	stty "\$line"
-EOF
-chmod +x "$BINARIES_DIR/qemu.sh"