Revert "Use broadcast SIPI to startup siblings"

This reverts commit 042c1461fb.

It turned out that sending IPIs via broadcast doesn't work on
Sandybridge. We tried to come up with a solution, but didn't
found any so far. So revert the code for now until we have
a working solution.

Change-Id: I7dd1cba5a4c1e4b0af366b20e8263b1f6f4b9714
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-on: http://review.coreboot.org/1381
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/cpu/intel/socket_LGA771/Kconfig

@@ -3,3 +3,4 @@ config CPU_INTEL_SOCKET_LGA771
         select CPU_INTEL_MODEL_6FX
 	select SSE2
 	select MMX
+	select AP_IN_SIPI_WAIT