qemu: zero ioport_opaque on isa_unassign_ioport (Marcelo Tosatti)

If the io port is unassigned, the previous private pointer is
meaningless.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6606 c046a42c-6fe2-441c-8c8c-71466251a162

vl.c

@@ -404,6 +404,8 @@ void isa_unassign_ioport(int start, int length)
         ioport_write_table[0][i] = default_ioport_writeb;
         ioport_write_table[1][i] = default_ioport_writew;
         ioport_write_table[2][i] = default_ioport_writel;
+
+        ioport_opaque[i] = NULL;
     }
 }