Impact: cleanup

In preparation for unifying irqinit_{32,64}.c, make
x86_quirk_pre_intr_init() local to irqinit_32.c.

Reviewed-by Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NIngo Molnar <mingo@elte.hu>