sysctl: set variable sysctl_mount_point storage-class-specifier to static

smatch reports
fs/proc/proc_sysctl.c:32:18: warning: symbol
  'sysctl_mount_point' was not declared. Should it be static?

This variable is only used in its defining file, so it should be static.
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

fs/proc/proc_sysctl.c

@@ -29,7 +29,7 @@ static const struct file_operations proc_sys_dir_file_operations;
 static const struct inode_operations proc_sys_dir_operations;
 
 /* Support for permanently empty directories */
-struct ctl_table sysctl_mount_point[] = {
+static struct ctl_table sysctl_mount_point[] = {
 	{.type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY }
 };