linux/cpumask.h: add typechecking to cpumask_test_cpu

The Subtlety (1) referred to vanished with 6ba2ef7b ("cpumask:
Move deprecated functions to end of header."). That used to mention
some suboptimal code generation by a, by now, rather ancient gcc. With
gcc 4.7, I don't see any change in the generated code by making it a
static inline, so let's add type checking and get rid of the ghost
reference.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

include/linux/cpumask.h

@@ -290,11 +290,11 @@ static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp)
  * @cpumask: the cpumask pointer
  *
  * Returns 1 if @cpu is set in @cpumask, else returns 0
- *
- * No static inline type checking - see Subtlety (1) above.
  */
-#define cpumask_test_cpu(cpu, cpumask) \
-	test_bit(cpumask_check(cpu), cpumask_bits((cpumask)))
+static inline int cpumask_test_cpu(int cpu, const struct cpumask *cpumask)
+{
+	return test_bit(cpumask_check(cpu), cpumask_bits((cpumask)));
+}
 
 /**
  * cpumask_test_and_set_cpu - atomically test and set a cpu in a cpumask