[IA64] Cleanup HPSIM code (was: Re: Enable early console for Ski simulator)

After my last patch we have a new header file for HP simulator use.
Here's code to use it for stuff that used to have `extern' statements
inline in the code.  Functionality should not change with this patch.

Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/hp/sim/simscsi.c

@@ -14,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/timer.h>
 #include <asm/irq.h>
+#include "hpsim_ssc.h"
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
@@ -59,8 +60,6 @@ struct disk_stat {
 	unsigned count;
 };
 
-extern long ia64_ssc (long arg0, long arg1, long arg2, long arg3, int nr);
-
 static int desc[16] = {
 	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
 };