slub: remove useless EXPORT_SYMBOL

kmem_cache_open is static. EXPORT_SYMBOL was leftover from some earlier
time period where kmem_cache_open was usable outside of slub.

(Fixes powerpc build error)
Signed-off-by: Chrsitoph Lameter <clameter@sgi.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slub.c

@@ -2020,7 +2020,6 @@ error:
 			s->offset, flags);
 	return 0;
 }
-EXPORT_SYMBOL(kmem_cache_open);
 
 /*
  * Check if a given pointer is valid