Refactoring perf metric support to remove branching on bundle type in the dispatch wrapper. This change includes caching the rdpmc index at perfmon_start(), so that the mmap_page.index doesn't need to be looked up each time. It also exclude the effects of mmap_page.index. This patch prepares the path for bundles that support general, fixed and metrics counters simulataneously. Type: refactor Signed-off-by: Ray Kinsella <mdr@ashroe.eu> Change-Id: I9c5b4917bd02fea960e546e8558452c4362eabc4