perf scripts python: exported-sql-viewer.py: Fix copy to clipboard from Top Calls by elapsed Time report

Provide missing argument to prevent following error when copying a
selection to the clipboard:

Traceback (most recent call last):
  File "tools/perf/scripts/python/exported-sql-viewer.py", line 4041, in <lambda>
    menu.addAction(CreateAction("&Copy selection", "Copy to clipboard", lambda: CopyCellsToClipboardHdr(self.view), self.view))
  File "tools/perf/scripts/python/exported-sql-viewer.py", line 4021, in CopyCellsToClipboardHdr
    CopyCellsToClipboard(view, False, True)
  File "tools/perf/scripts/python/exported-sql-viewer.py", line 4018, in CopyCellsToClipboard
    view.CopyCellsToClipboard(view, as_csv, with_hdr)
  File "tools/perf/scripts/python/exported-sql-viewer.py", line 3871, in CopyTableCellsToClipboard
    val = model.headerData(col, Qt.Horizontal)
TypeError: headerData() missing 1 required positional argument: 'role'

Fixes: 96c43b9a ("perf scripts python: exported-sql-viewer.py: Add copy to clipboard")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20210521092053.25683-2-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>