[PATCH] i386: Fix fake return address

The fake return address was being set to __KERNEL_PDA, rather than 0.
Push it earlier while %eax still equals 0.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Andrew Morton <akpm@osdl.org>