[IA64] Enable early console for Ski simulator

This patch cleans up the `enable early console for SKI' patch
(471e7a4484), and
1. potentially allows the gensparse_defconfig to work again.
   (there are other problems running a generic kernel on Ski)
2. fixes the `console registered twice' problem.
3. Cleans up the code by moving the `extern hpsim_cons' declaration to
   a new asm/hpsim.h file.

Thanks to Jes for comments.

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

arch/ia64/kernel/setup.c

@@ -60,6 +60,7 @@
 #include <asm/smp.h>
 #include <asm/system.h>
 #include <asm/unistd.h>
+#include <asm/hpsim.h>
 
 #if defined(CONFIG_SMP) && (IA64_CPU_SIZE > PAGE_SIZE)
 # error "struct cpuinfo_ia64 too big!"
@@ -389,13 +390,8 @@ early_console_setup (char *cmdline)
 	if (!efi_setup_pcdp_console(cmdline))
 		earlycons++;
 #endif
-#ifdef CONFIG_HP_SIMSERIAL_CONSOLE
-	{
-		extern struct console hpsim_cons;
-		register_console(&hpsim_cons);
+	if (!simcons_register())
 		earlycons++;
-	}
-#endif
 
 	return (earlycons) ? 0 : -1;
 }