kernel/hung_task.c: set some hung_task.c variables storage-class-specifier to static

smatch reports several warnings
kernel/hung_task.c:31:19: warning:
  symbol 'sysctl_hung_task_check_count' was not declared. Should it be static?
kernel/hung_task.c:50:29: warning:
  symbol 'sysctl_hung_task_check_interval_secs' was not declared. Should it be static?
kernel/hung_task.c:52:19: warning:
  symbol 'sysctl_hung_task_warnings' was not declared. Should it be static?
kernel/hung_task.c:75:28: warning:
  symbol 'sysctl_hung_task_panic' was not declared. Should it be static?

These variables are only used in hung_task.c, so they should be static

Link: https://lkml.kernel.org/r/20230312164645.471259-1-trix@redhat.comSigned-off-by: Tom Rix <trix@redhat.com>
Cc: Ben Dooks <ben.dooks@sifive.com>
Cc: fuyuanli <fuyuanli@didiglobal.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/hung_task.c

@@ -28,7 +28,7 @@
 /*
  * The number of tasks checked:
  */
-int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
+static int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
 
 /*
  * Limit number of tasks checked in a batch.
@@ -47,9 +47,9 @@ unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_
 /*
  * Zero (default value) means use sysctl_hung_task_timeout_secs:
  */
-unsigned long __read_mostly sysctl_hung_task_check_interval_secs;
+static unsigned long __read_mostly sysctl_hung_task_check_interval_secs;
 
-int __read_mostly sysctl_hung_task_warnings = 10;
+static int __read_mostly sysctl_hung_task_warnings = 10;
 
 static int __read_mostly did_panic;
 static bool hung_task_show_lock;
@@ -72,7 +72,7 @@ static unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace;
  * Should we panic (and reboot, if panic_timeout= is set) when a
  * hung task is detected:
  */
-unsigned int __read_mostly sysctl_hung_task_panic =
+static unsigned int __read_mostly sysctl_hung_task_panic =
 	IS_ENABLED(CONFIG_BOOTPARAM_HUNG_TASK_PANIC);
 
 static int