perf symbols: Make sym->end be the first address after the symbol range

To follow vm_area_struct->vm_end convention.

By adhering to the convention that ->end is the first address outside
the symbol's range we can do things like:

	sym->end = start + len;
	len = sym->end - sym->start;

This is also now the convention used for struct map->end, fixing some
off-by-one bugs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-agomujr7tuqaq6lu7kr6z7h6@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>