staging: lustre: fix build breakage on microblaze

I missed an include path that microblaze found in it's build paths.

Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: hpdd-discuss <hpdd-discuss@lists.01.org>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/include/linux/libcfs/linux/linux-mem.h

@@ -54,7 +54,7 @@
 
 #ifndef HAVE_LIBCFS_CPT
 /* Need this for cfs_cpt_table */
-#include <linux/libcfs/libcfs_cpu.h>
+#include "../libcfs_cpu.h"
 #endif
 
 #define CFS_PAGE_MASK		   (~((__u64)PAGE_CACHE_SIZE-1))