perf tools: Adjust symbols in VDSO

pert-report doesn't resolve function names in VDSO:

$ perf report --stdio -g flat,0.0,15,callee --sort pid
..
            8.76%
               0x7fff6b1fe861
               __gettimeofday
               ACE_OS::gettimeofday()
..

In this case symbol values should be adjusted the same way as for executables, relocatable objects and prelinked libraries.

After fix:

$ perf report --stdio -g flat,0.0,15,callee --sort pid
..
            8.76%
               __vdso_gettimeofday
               __gettimeofday
               ACE_OS::gettimeofday()

Signed-off-by: Vladimir Nikulichev <nvs@tbricks.com>

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 3b7dbf5..6864661 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -6,6 +6,7 @@
#include <inttypes.h>

#include "symbol.h"
+#include "vdso.h"
#include <symbol/kallsyms.h>
#include "debug.h"

@@ -618,6 +619,7 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
		GElf_Shdr shdr;
		ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
				ehdr.e_type == ET_REL ||
+				is_vdso_map(dso->short_name) ||
				elf_section_by_name(elf, &ehdr, &shdr,
						     ".gnu.prelink_undo",
						     NULL) != NULL);