perf symbols: Record text offset in dso to calculate objdump address

perf symbols: Record text offset in dso to calculate objdump address

Store DSO's .text offset into DSO, used for VDSOs and will also be used for
other needs, like handling kernel modules.

Signed-off-by: Wang Nan <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Cody P Schafer <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kirill Smelkov <[email protected]>
Cc: Li Zefan <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
[ Extracted from larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>