When using Ski to debug early startup, it's a bit of a pain not to
have printk.

This patch enables the simulated console very early.
It may be worth conditionalising on the command line... but this is
enough for now.
Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>