perf tools: Allow ability to map cpus to nodes easily

This patch figures out the max number of cpus and nodes that are on the
system and creates a map of cpu to node.  This allows us to provide a cpu
and quickly get the node associated with it.

It was mostly copied from builtin-kmem.c and tweaked slightly to use less memory
(use possible cpus instead of max).  It also calculates the max number of nodes.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1396896924-129847-2-git-send-email-dzickus@redhat.com


[ Removing out label code in init_cpunode_map ]
[ Adding check for snprintf error ]
[ Removing unneeded returns ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>