fix this build warning:
 include/asm/topology_32.h: In function 'node_to_first_cpu':
 include/asm/topology_32.h:66: warning: unused variable 'mask'
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 int __next_cpu(int n, const cpumask_t *srcp);
 #define next_cpu(n, src) __next_cpu((n), &(src))
 #else
-#define first_cpu(src)         0
-#define next_cpu(n, src)       1
+#define first_cpu(src)         ({ (void)(src); 0; })
+#define next_cpu(n, src)       ({ (void)(src); 1; })
 #endif
 
 #define cpumask_of_cpu(cpu)                                            \