powercap: intel_rapl: remove redundant store to value after multiply

There is no need to store the result of the multiply back to variable value
after the multiplication. The store is redundant, replace *= with just *.

Cleans up clang scan build warning:
warning: Although the value stored to 'value' is used in the enclosing
expression, the value is never actually read from 'value'
[deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: ColinIanKing

drivers/powercap/intel_rapl_common.c

@@ -1010,7 +1010,7 @@ static u64 rapl_compute_time_window_atom(struct rapl_package *rp, u64 value,
 	 * where time_unit is default to 1 sec. Never 0.
 	 */
 	if (!to_raw)
-		return (value) ? value *= rp->time_unit : rp->time_unit;
+		return (value) ? value * rp->time_unit : rp->time_unit;
 
 	value = div64_u64(value, rp->time_unit);