x86: remove simnow earlyprintk support

Impact: remove obsolete code

The later versions of SimNow! actually all have serial console
emulation, so the direct interface isn't needed anymore. So remove
the undocumented simnow earlyprintk console.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>