feat(panic): Display panic message on the display

Currently, panics will silently reboot if the user doesn't happen to
look at the serial console when it happens.  To give a bit more
feedback, display @msgctl's faultsplash and the panic messages as well.

Co-authored-by: Mateusz Zalega <mateusz@appliedsourcery.com>
Signed-off-by: Rahix <rahix@rahix.de>