So that we can remove dso.h from symbol.h and reduce the header
dependency tree.
Fixup cases where struct dso guts are needed but were obtained via
symbol.h, indirectly.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-ip683cegt306ncu3gsz7ii21@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>