siemens/sitemp_g1p1: Don't mess with virtual wire settings

That function broke SMP on Linux 2.4, now it works.

Change-Id: I4ddd25fef57bed64877959ca96cca68170042bca
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Reviewed-on: http://review.coreboot.org/243
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>