add check to cpumask_of()

Just like any other function's CPU inputs, the one here shouldn't go
unchecked.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>

xen/include/xen/cpumask.h

@@ -304,7 +304,9 @@ extern const unsigned long
 
 static inline const cpumask_t *cpumask_of(unsigned int cpu)
 {
-	const unsigned long *p = cpu_bit_bitmap[1 + cpu % BITS_PER_LONG];
+	const unsigned long *p = cpu_bit_bitmap[1 + cpumask_check(cpu) %
+                                                   BITS_PER_LONG];
+
 	return (const cpumask_t *)(p - cpu / BITS_PER_LONG);
 }