perf probe: Support DW_OP_plus_uconst in DW_AT_data_member_location

DW_OP_plus_uconst can be used for DW_AT_data_member_location.
This patch adds DW_OP_plus_uconst support when getting
structure member offset.

Commiter note:

Fixed up the size_t format specifier in one case:

cc1: warnings being treated as errors
util/probe-finder.c: In function ‘die_get_data_member_location’:
util/probe-finder.c:270: error: format ‘%d’ expects type ‘int’, but argument 4 has type ‘size_t’
make: *** [/home/acme/git/build/perf/util/probe-finder.o] Error 1

LKML-Reference: <20100414223958.14630.5230.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>