clean up mpintrprint

Reference: /n/atom/patch/applied2013/nixmpintrpr
Date: Sat Sep 14 21:45:10 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/k10/mp.c	Sat Sep 14 21:45:01 2013
+++ /sys/src/nix/k10/mp.c	Sat Sep 14 21:45:02 2013
@@ -55,16 +55,13 @@
 static void
 mpintrprint(char* s, u8int* p)
 {
-	char buf[128], *b, *e;
-	char format[] = " type %d flags %#ux bus %d IRQ %d APIC %d INTIN %d\n";
+	char buf[64];
 
-	b = buf;
-	e = b + sizeof(buf);
-	b = seprint(b, e, "mpparse: intr:");
+	buf[0] = 0;
 	if(s != nil)
-		b = seprint(b, e, " %s:", s);
-	seprint(b, e, format, p[1], l16get(p+2), p[4], p[5], p[6], p[7]);
-	print(buf);
+		snprint(buf, sizeof buf, " %s:", s);
+	print("mpparse: intr:%s type %d flags %#ux bus %d irq %d apic %d intin %d",
+		buf, p[1], l16get(p+2), p[4], p[5], p[6], p[7]);
 }
 
 static u32int