tools: timers: fix freq average calculation

Delete a duplicate assignment from this function implementation.
The note means ppm is average of the two actual freq samples.
But ppm have a duplicate assignment.

Signed-off-by: Minjie Du <duminjie@vivo.com>
Acked-by: John Stultz <jstultz@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Author: Minjie Du

tools/testing/selftests/timers/raw_skew.c

@@ -129,8 +129,7 @@ int main(int argc, char **argv)
 	printf("%lld.%i(est)", eppm/1000, abs((int)(eppm%1000)));
 
 	/* Avg the two actual freq samples adjtimex gave us */
-	ppm = (tx1.freq + tx2.freq) * 1000 / 2;
-	ppm = (long long)tx1.freq * 1000;
+	ppm = (long long)(tx1.freq + tx2.freq) * 1000 / 2;
 	ppm = shift_right(ppm, 16);
 	printf(" %lld.%i(act)", ppm/1000, abs((int)(ppm%1000)));