perf unwind-libunwind: Fix base address for .eh_frame

The base address of a DSO mapping should start at the start of the file.
Usually DSOs are mapped from the pgoff 0 so it doesn't matter when it
uses the start of the map address.

But generated DSOs for JIT codes doesn't start from the 0 so it should
subtract the offset to calculate the .eh_frame table offsets correctly.

Fixes: dc2cf4ca ("perf unwind: Fix segbase for ld.lld linked objects")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Fangrui Song <maskray@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Pablo Galindo <pablogsal@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231212070547.612536-4-namhyung@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>