cpumask: Fix typo nr_cpumask_size --> nr_cpumask_bits

The never used nr_cpumask_size is just a typo, hence use existing
redefinition that's called nr_cpumask_bits.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 8fbe766..ce8eb7e 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -66,7 +66,7 @@
  * Finally, some operations just want the exact limit, either because
  * they set bits or just don't have any faster fixed-sized versions. We
- * call this just 'nr_cpumask_size'.
+ * call this just 'nr_cpumask_bits'.
  * Note that these optional constants are always guaranteed to be at
  * least as big as 'nr_cpu_ids' itself is, and all our cpumask