powerpc/xmon: Define static functions

Currently sparse is complaining about three issues on the xmon code. Two
storage classes issues and a dereferencing a 'noderef'  pointer. These are
the warnings:

	arch/powerpc/xmon/xmon.c:2783:1: warning: symbol 'dump_log_buf' was not declared. Should it be static?
	arch/powerpc/xmon/xmon.c:2989:6: warning: symbol 'format_pte' was not declared. Should it be static?
	arch/powerpc/xmon/xmon.c:2983:30: warning: dereference of noderef expression

This patch fixes all of them, turning both functions static and
dereferencing a pointer calling rcu_dereference() instead of a
straightforward dereference.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/xmon/xmon.c

@@ -2793,7 +2793,7 @@ print_address(unsigned long addr)
 	xmon_print_symbol(addr, "\t# ", "");
 }
 
-void
+static void
 dump_log_buf(void)
 {
 	struct kmsg_dumper dumper = { .active = 1 };
@@ -2994,13 +2994,13 @@ static void show_task(struct task_struct *tsk)
 
 	printf("%px %016lx %6d %6d %c %2d %s\n", tsk,
 		tsk->thread.ksp,
-		tsk->pid, tsk->parent->pid,
+		tsk->pid, rcu_dereference(tsk->parent)->pid,
 		state, task_thread_info(tsk)->cpu,
 		tsk->comm);
 }
 
 #ifdef CONFIG_PPC_BOOK3S_64
-void format_pte(void *ptep, unsigned long pte)
+static void format_pte(void *ptep, unsigned long pte)
 {
 	pte_t entry = __pte(pte);