perf report: Fix condition in sort__sym_cmp()

perf report: Fix condition in sort__sym_cmp()

It's expected that both hist entries are in the same hists when
comparing two.  But the current code in the function checks one without
dso sort key and other with the key.  This would make the condition true
in any case.

I guess the intention of the original commit was to add '!' for the
right side too.  But as it should be the same, let's just remove it.

Fixes: 69849fc5d2119 ("perf hists: Move sort__has_dso into struct perf_hpp_list")
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240621170528.608772-2-namhyung@kernel.org