perf probe: Fix type searching

Fix to get the actual type die of variables by using dwarf_attr_integrate()
which gets attribute from die even if the type die is connected by
DW_AT_abstract_origin.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20101021101302.3542.38549.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>