powerpc/tau: Make some function static

These functions can all be static, make it so. Fix warnings treated as
errors with W=1:

  arch/powerpc/kernel/tau_6xx.c:53:6: error: no previous prototype for ‘set_thresholds’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:73:6: error: no previous prototype for ‘TAUupdate’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:208:13: error: no previous prototype for ‘TAU_init_smp’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:220:12: error: no previous prototype for ‘TAU_init’ [-Werror=missing-prototypes]
  arch/powerpc/kernel/tau_6xx.c:126:6: error: no previous prototype for ‘TAUException’ [-Werror=missing-prototypes]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/tau_6xx.c

@@ -53,7 +53,7 @@ struct timer_list tau_timer;
 #define shrink_timer	2*HZ	/* period between shrinking the window */
 #define min_window	2	/* minimum window size, degrees C */
 
-void set_thresholds(unsigned long cpu)
+static void set_thresholds(unsigned long cpu)
 {
 #ifdef CONFIG_TAU_INT
 	/*
@@ -73,7 +73,7 @@ void set_thresholds(unsigned long cpu)
 #endif
 }
 
-void TAUupdate(int cpu)
+static void TAUupdate(int cpu)
 {
 	unsigned thrm;
 
@@ -208,7 +208,7 @@ static void tau_timeout_smp(struct timer_list *unused)
 
 int tau_initialized = 0;
 
-void __init TAU_init_smp(void * info)
+static void __init TAU_init_smp(void *info)
 {
 	unsigned long cpu = smp_processor_id();
 
@@ -220,7 +220,7 @@ void __init TAU_init_smp(void * info)
 	set_thresholds(cpu);
 }
 
-int __init TAU_init(void)
+static int __init TAU_init(void)
 {
 	/* We assume in SMP that if one CPU has TAU support, they
 	 * all have it --BenH