perf evsel: No need to include symbol.h in evsel.h, symbol_conf.h is enough

To reduce the header dependency and avoid unnecessary rebuilds when
things change in symbol.h.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-6duflwliprh2tr47w5x4t260@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evsel.h

@@ -8,7 +8,7 @@
 #include <linux/perf_event.h>
 #include <linux/types.h>
 #include "xyarray.h"
-#include "symbol.h"
+#include "symbol_conf.h"
 #include "cpumap.h"
 #include "counts.h"