Make lib/raid6/test build correctly.

Some bit-rot needs to be cleaned out.

Signed-off-by: NeilBrown <neilb@suse.de>

lib/raid6/algos.c

@@ -17,11 +17,11 @@
  */
 
 #include <linux/raid/pq.h>
-#include <linux/gfp.h>
 #ifndef __KERNEL__
 #include <sys/mman.h>
 #include <stdio.h>
 #else
+#include <linux/gfp.h>
 #if !RAID6_USE_EMPTY_ZERO_PAGE
 /* In .bss so it's zeroed */
 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));