[POWERPC] pasemi idle uses hard_smp_processor_id

and so needs to include asm/smp.h so a UP build works.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>