powerpc: convert to generic helpers for IPI function calls

This converts ppc to use the new helpers for smp_call_function() and
friends, and adds support for smp_call_function_single().

ppc loses the timeout functionality of smp_call_function_mask() with
this change, as the generic code does not provide that.

Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 7680001..6c90c95 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -1494,7 +1494,7 @@
 	static char *ipi_names[] = {
 		"IPI0 (call function)",
 		"IPI1 (reschedule)",
-		"IPI2 (unused)",
+		"IPI2 (call function single)",
 		"IPI3 (debugger break)",
 	};
 	BUG_ON(mpic == NULL);