sh: remove cpu_online() definition from <asm/smp.h>

It's defined in <linux/cpumask.h> and log is horribly flooded by
"redefined" messages.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/asm-sh/smp.h

@@ -19,11 +19,6 @@
 #include <asm/atomic.h>
 #include <asm/current.h>
 
-extern cpumask_t cpu_online_map;
-extern cpumask_t cpu_possible_map;
-
-#define cpu_online(cpu)		cpu_isset(cpu, cpu_online_map)
-
 #define raw_smp_processor_id()	(current_thread_info()->cpu)
 
 /* I've no idea what the real meaning of this is */