Undo change from this morning that wasn't intended to get in.

40a2a083 · rsc · 643b122b · 40a2a083
--- a/picirq.c
+++ b/picirq.c
@@ -53,7 +53,7 @@ pic_init(void)
  outb(IO_PIC2+1, IRQ_SLAVE);		// ICW3
  // NB Automatic EOI mode doesn't tend to work on the slave.
  // Linux source code says it's "to be investigated".
-  outb(IO_PIC2+1, 0x1);			// ICW4
+  outb(IO_PIC2+1, 0x3);			// ICW4

  // OCW3:  0ef01prs
  //   ef:  0x = NOP, 10 = clear specific mask, 11 = set specific mask