sparc64: Make proc_id signed.

So that when it is unset, ie. '-1', userspace can see it
properly.
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/cpudata_64.h

@@ -28,7 +28,7 @@ typedef struct {
 	unsigned short	sock_id;	/* physical package */
 	unsigned short	core_id;
 	unsigned short  max_cache_id;	/* groupings of highest shared cache */
-	unsigned short	proc_id;	/* strand (aka HW thread) id */
+	signed short	proc_id;	/* strand (aka HW thread) id */
 } cpuinfo_sparc;
 
 DECLARE_PER_CPU(cpuinfo_sparc, __cpu_data);