DocBook: include !Emm/util.c in kernel-api to include, kzfree and more

Add the exported symbols from mm/util.c to the kernel-api memory
management section, to pick up obvious routines like kzfree and
krealloc.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: Rob Landley <rob@landley.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Documentation/DocBook/kernel-api.tmpl

@@ -109,6 +109,7 @@ X!Ilib/string.c
      <sect1><title>The Slab Cache</title>
 !Iinclude/linux/slab.h
 !Emm/slab.c
+!Emm/util.c
      </sect1>
      <sect1><title>User Space Memory Access</title>
 !Iarch/x86/include/asm/uaccess_32.h