perf tools: Move dso_* related functions into dso object

perf tools: Move dso_* related functions into dso object

Moving dso_* related functions into dso object.

Keeping symbol loading related functions still in the symbol object as
it seems more convenient.

Signed-off-by: Jiri Olsa <[email protected]>
Reviewed-by: Namhyung Kim <[email protected]>
Tested-by: Namhyung Kim <[email protected]>
Cc: Corey Ashford <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ committer note: Use "symbol.h" instead of <symbol.h> to make it build with O= ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>