timebase: Remove unused remaining time calculation

In db9c142 ("Improve cpu_idle when PM is disabled") the
time_wait_poll calculation was modified to calculate the remaining time
on each loop. Because of this we don't need to decrement remaining any
more.

Found by scan-build.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

core/timebase.c

@@ -41,7 +41,6 @@ static void time_wait_poll(unsigned long duration)
 		if (remaining >= period) {
 			opal_run_pollers();
 			time_wait_nopoll(period);
-			remaining -= period;
 		} else
 			time_wait_nopoll(remaining);