ARM: 9334/1: mm: init: remove misuse of kernel-doc comment

Change the "/**" beginning of comment to the common "/*" comment
since the comment is not in kernel-doc format. This prevents a
kernel-doc warning:

arch/arm/mm/init.c:422: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * update_sections_early intended to be called only through stop_machine

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: patches@armlinux.org.uk
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>