perf symbols: Keep DSO->symtab_type after decompress

perf symbols: Keep DSO->symtab_type after decompress

The symsrc__init() overwrites dso->symtab_type as symsrc->type in
dso__load_sym().  But for compressed kernel modules in the build-id
cache, it should have original symtab type to be decompressed as needed.

This fixes perf annotate to show disassembly of the function properly.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170608073109.30699-9-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>