[PATCH] i386: add alternative-asm.h to allow LOCK_PREFIX replacement in .S files

LOCK_PREFIX is replaced by nops on UP systems, so it has to be a special
macro.  Previously this was only possible from C. Allow it for pure
assembly files too. Similar to earlier x86-64 patch.
Signed-off-by: Andi Kleen <ak@suse.de>