Fix quilt merge error in acpi-cpufreq.c

We ended up incorrectly using '&cur' instead of '&readin' in the
work_on_cpu() -> smp_call_function_single() transformation in commit
01599fca6758d2cd133e78f87426fc851c9ea725 ("cpufreq: use
smp_call_function_[single|many]() in acpi-cpufreq.c").

Andrew explains:
 "OK, the acpi tree went and had conflicting changes merged into it after
  I'd written the patch and it appears that I incorrectly reverted part
  of 18b2646fe3babeb40b34a0c1751e0bf5adfdc64c while fixing the resulting
  rejects.

  Switching it to `readin' looks correct."

Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c

@@ -277,7 +277,7 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy,
 	unsigned int perf_percent;
 	unsigned int retval;
 
-	if (smp_call_function_single(cpu, read_measured_perf_ctrs, &cur, 1))
+	if (smp_call_function_single(cpu, read_measured_perf_ctrs, &readin, 1))
 		return 0;
 
 	cur.aperf.whole = readin.aperf.whole -