mkosi: Drop workaround to re-enable serial console line wrapping

Since we do it in reset_terminal_fd() now, there's no need to carry
this workaround anymore.

mkosi.images/system/mkosi.postinst.chroot

@@ -2,10 +2,6 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 set -e
 
-# Make sure serial console line wrapping is re-enabled as qemu's seabios firmware disables serial console
-# line-wrapping on boot.
-echo "tput smam || :" >>/etc/profile
-
 if [ -n "$SANITIZERS" ]; then
     LD_PRELOAD=$(ldd /usr/lib/systemd/systemd | grep libasan.so | awk '{print $3}')