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

# fujitsu
Cc: David Howells

# ia64
Cc: Tony Luck

# powerpc
Cc: Paul Mackerras
Cc: Anton Blanchard

# sparc
Cc: David S. Miller
Cc: William L. Irwin

# x86
Cc: H. Peter Anvin

Signed-off-by: Mike Travis
Signed-off-by: Ingo Molnar