x86/unwind/orc: Convert global variables to static

These variables aren't used outside of unwind_orc.c, make them static.

Also annotate some of them with '__ro_after_init', as applicable.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Jones <dsj@fb.com>
Cc: Jann Horn <jannh@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lore.kernel.org/r/43ae310bf7822b9862e571f36ae3474cfde8f301.1587808742.git.jpoimboe@redhat.com

arch/x86/kernel/unwind_orc.c

@@ -15,12 +15,12 @@ extern int __stop_orc_unwind_ip[];
 extern struct orc_entry __start_orc_unwind[];
 extern struct orc_entry __stop_orc_unwind[];
 
-static DEFINE_MUTEX(sort_mutex);
-int *cur_orc_ip_table = __start_orc_unwind_ip;
-struct orc_entry *cur_orc_table = __start_orc_unwind;
+static bool orc_init __ro_after_init;
+static unsigned int lookup_num_blocks __ro_after_init;
 
-unsigned int lookup_num_blocks;
-bool orc_init;
+static DEFINE_MUTEX(sort_mutex);
+static int *cur_orc_ip_table = __start_orc_unwind_ip;
+static struct orc_entry *cur_orc_table = __start_orc_unwind;
 
 static inline unsigned long orc_ip(const int *ip)
 {