mips: smp: fix setup_profiling_timer() prototype

The function is unconditionally defined in smp.c but is conditionally
declared in a header that is not included here.

arch/mips/kernel/smp.c:473:5: error: no previous prototype for 'setup_profiling_timer' [-Werror=missing-prototypes]

Add the missing #include and #ifdef to match the declaration.

Link: https://lkml.kernel.org/r/20231204115710.2247097-20-arnd@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Rothwell <sfr@rothwell.id.au>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/mips/kernel/smp.c

@@ -10,6 +10,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
+#include <linux/profile.h>
 #include <linux/smp.h>
 #include <linux/spinlock.h>
 #include <linux/threads.h>
@@ -468,11 +469,13 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 	return 0;
 }
 
+#ifdef CONFIG_PROFILING
 /* Not really SMP stuff ... */
 int setup_profiling_timer(unsigned int multiplier)
 {
 	return 0;
 }
+#endif
 
 static void flush_tlb_all_ipi(void *info)
 {