ppc: Minor smp changes for consistency with ppc64

This makes platform code use the smp_ops variable directly instead
of ppc_md.smp_ops, removes the two unused `data' and `wait' arguments
from the *_message_pass() functions, and removes the call to the
never-implemented smp_ops->space_timers() function.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/ppc/platforms/pplus.c b/arch/ppc/platforms/pplus.c
index c880321..59eb330 100644
--- a/arch/ppc/platforms/pplus.c
+++ b/arch/ppc/platforms/pplus.c
@@ -903,6 +903,6 @@
 	ppc_md.kgdb_map_scc = gen550_kgdb_map_scc;
 #endif
 #ifdef CONFIG_SMP
-	ppc_md.smp_ops = &pplus_smp_ops;
+	smp_ops = &pplus_smp_ops;
 #endif				/* CONFIG_SMP */
 }