problem found by cinap.  don't touch Isrc2 in ifstats(), as this will
turn interrupts off.  potentially forever.

Reference: /n/atom/patch/applied/yukifstats
Date: Mon Jan 13 15:07:27 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/pcpae/etheryuk.c	Mon Jan 13 15:06:16 2014
+++ /sys/src/9/pcpae/etheryuk.c	Mon Jan 13 15:06:18 2014
@@ -1825,7 +1825,7 @@
 			p = seprint(p, e, "%s\t%ud\n", stattab[i].name, u);
 	}
 	p = seprint(p, e, "stat %.4ux ctl %.3ux\n", gmacread(c, Stat), gmacread(c, Ctl));
-	p = seprint(p, e, "irq %.8ux\n", c->reg[Isrc2]);
+//	p = seprint(p, e, "irq %.8ux\n", c->reg[Isrc2]);
 	p = seprint(p, e, "pref %.8ux %.4ux\n", prread32(c, Qr + Pctl), prread16(c, Qr + Pgetidx));
 	p = seprint(p, e, "nfast %ud nslow %ud\n", rbtab[c->qno].nfast, rbtab[c->qno].nslow);
 	if(debug){
--- /sys/src/9/pc/etheryuk.c	Mon Jan 13 15:06:20 2014
+++ /sys/src/9/pc/etheryuk.c	Mon Jan 13 15:06:22 2014
@@ -1825,7 +1825,7 @@
 			p = seprint(p, e, "%s\t%ud\n", stattab[i].name, u);
 	}
 	p = seprint(p, e, "stat %.4ux ctl %.3ux\n", gmacread(c, Stat), gmacread(c, Ctl));
-	p = seprint(p, e, "irq %.8ux\n", c->reg[Isrc2]);
+//	p = seprint(p, e, "irq %.8ux\n", c->reg[Isrc2]);
 	p = seprint(p, e, "pref %.8ux %.4ux\n", prread32(c, Qr + Pctl), prread16(c, Qr + Pgetidx));
 	p = seprint(p, e, "nfast %ud nslow %ud\n", rbtab[c->qno].nfast, rbtab[c->qno].nslow);
 	if(debug){