mm: compaction: remove incorrect #ifdef checks

Without CONFIG_SYSCTL, the compiler warns about a few unused functions:

mm/compaction.c:3076:12: error: 'proc_dointvec_minmax_warn_RT_change' defined but not used [-Werror=unused-function]
mm/compaction.c:2780:12: error: 'sysctl_compaction_handler' defined but not used [-Werror=unused-function]
mm/compaction.c:2750:12: error: 'compaction_proactiveness_sysctl_handler' defined but not used [-Werror=unused-function]

The #ifdef is actually not necessary here, as the alternative
register_sysctl_init() stub function does not use its argument, which
lets the compiler drop the rest implicitly, while avoiding the warning.

Fixes: c521126610c3 ("mm: compaction: move compaction sysctl to its own file")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

mm/compaction.c

@@ -3080,7 +3080,6 @@ static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table,
 	return ret;
 }
 
-#ifdef CONFIG_SYSCTL
 static struct ctl_table vm_compaction[] = {
 	{
 		.procname	= "compact_memory",
@@ -3118,7 +3117,6 @@ static struct ctl_table vm_compaction[] = {
 	},
 	{ }
 };
-#endif
 
 static int __init kcompactd_init(void)
 {
@@ -3135,9 +3133,7 @@ static int __init kcompactd_init(void)
 
 	for_each_node_state(nid, N_MEMORY)
 		kcompactd_run(nid);
-#ifdef CONFIG_SYSCTL
 	register_sysctl_init("vm", vm_compaction);
-#endif
 	return 0;
 }
 subsys_initcall(kcompactd_init)