s390: Move s390 sysctls into their own file under arch/s390

Move s390 sysctls (spin_retry and userprocess_debug) into their own
files under arch/s390. Create two new sysctl tables
(2390_{fault,spin}_sysctl_table) which will be initialized with
arch_initcall placing them after their original place in proc_root_init.

This is part of a greater effort to move ctl tables into their
respective subsystems which will reduce the merge conflicts in
kernel/sysctl.c.

Signed-off-by: joel granados <joel.granados@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250306-jag-mv_ctltables-v2-6-71b243c8d3f8@kernel.org
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

kernel/sysctl.c

@@ -1794,15 +1794,6 @@ static const struct ctl_table kern_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_MAXOLDUID,
 	},
-#ifdef CONFIG_S390
-	{
-		.procname	= "userprocess_debug",
-		.data		= &show_unhandled_signals,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-#endif
 	{
 		.procname	= "panic_on_oops",
 		.data		= &panic_on_oops,
@@ -1897,15 +1888,6 @@ static const struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 #endif
-#if defined(CONFIG_S390) && defined(CONFIG_SMP)
-	{
-		.procname	= "spin_retry",
-		.data		= &spin_retry,
-		.maxlen		= sizeof (int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
-#endif
 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
 	{
 		.procname	= "acpi_video_flags",