perf powerpc: Add missing headers to skip-callchain-idx.c

It uses several structs but don't explicitely includes the headers where
they are defined, getting them by sheer luck from one of the headers it
includes, since those are being streamlined to avoid unnecessary
rebuilds when changes are made to a random header, they will break, fix
them now so that they continue to build.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Maynard Johnson <maynard@us.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: https://lkml.kernel.org/n/tip-j1nyksegpnz36wi3qx2p46i1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>