[POWERPC] Add smp_call_function_map and smp_call_function_single

Add a new function named smp_call_function_single().  This matches a generic
prototype from include/linux/smp.h.

Add a function smp_call_function_map().  This is, for the most part, a rename
of smp_call_function, with some added cpumask support.  smp_call_function and
smp_call_function_single call into smp_call_function_map.

Lightly tested on 970mp (blade), power4 and power5.

Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>