x86: Make default_send_IPI_mask_sequence/allbutself_logical() 32bit only

Both functions are used only in 32bit.  Put them inside
CONFIG_X86_32. This is to prepare for logical apicid handling
update.

- Cyrill Gorcunov spotted that I forgot to move declarations in
ipi.h   under CONFIG_X86_32.  Fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: eric.dumazet@gmail.com
Cc: brgerst@gmail.com
Cc: shaohui.zheng@intel.com
Cc: rientjes@google.com
LKML-Reference: <1295789862-25482-4-git-send-email-tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>