cpufreq: intel_pstate: Remove core_pct rounding

The specific rounding adds conditionally only 1/256 to fractional
part of core_pct.

We can safely remove it without any noticeable impact in
calculations.

Use div64_u64 instead of div_u64 to avoid possible overflow of
sample->mperf as divisor

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/intel_pstate.c

@@ -545,13 +545,9 @@ static inline void intel_pstate_calc_busy(struct cpudata *cpu)
 {
 	struct sample *sample = &cpu->sample;
 	int64_t core_pct;
-	int32_t rem;
 
 	core_pct = int_tofp(sample->aperf) * int_tofp(100);
-	core_pct = div_u64_rem(core_pct, int_tofp(sample->mperf), &rem);
-
-	if ((rem << 1) >= int_tofp(sample->mperf))
-		core_pct += 1;
+	core_pct = div64_u64(core_pct, int_tofp(sample->mperf));
 
 	sample->freq = fp_toint(
 		mul_fp(int_tofp(cpu->pstate.max_pstate * 1000), core_pct));