asm-generic: add node_to_cpumask_ptr macro

Create a simple macro to always return a pointer to the node_to_cpumask(node)
value.  This relies on compiler optimization to remove the extra indirection:

    #define node_to_cpumask_ptr(v, node) 		\
	    cpumask_t _##v = node_to_cpumask(node), *v = &_##v

For those systems with a large cpumask size, then a true pointer
to the array element can be used:

    #define node_to_cpumask_ptr(v, node)		\
	    cpumask_t *v = &(node_to_cpumask_map[node])

A node_to_cpumask_ptr_next() macro is provided to access another
node_to_cpumask value.

The other change is to always include asm-generic/topology.h moving the
ifdef CONFIG_NUMA to this same file.

Note: there are no references to either of these new macros in this patch,
only the definition.

Based on 2.6.25-rc5-mm1

# alpha
Cc: Richard Henderson <[email protected]>

# fujitsu
Cc: David Howells <[email protected]>

# ia64
Cc: Tony Luck <[email protected]>

# powerpc
Cc: Paul Mackerras <[email protected]>
Cc: Anton Blanchard <[email protected]>

# sparc
Cc: David S. Miller <[email protected]>
Cc: William L. Irwin <[email protected]>

# x86
Cc: H. Peter Anvin <[email protected]>

Signed-off-by: Mike Travis <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

include/asm-alpha/topology.h

@@ -41,8 +41,7 @@ static inline cpumask_t node_to_cpumask(int node)
 
 #define pcibus_to_cpumask(bus)	(cpu_online_map)
 
-#else /* CONFIG_NUMA */
-# include <asm-generic/topology.h>
 #endif /* !CONFIG_NUMA */
+# include <asm-generic/topology.h>
 
 #endif /* _ASM_ALPHA_TOPOLOGY_H */