powerpc: Fix corruption error in rh_alloc_fixed()

There is an error in rh_alloc_fixed() of the Remote Heap code:
If there is at least one free block blk won't be NULL at the end of the
search loop, so -ENOMEM won't be returned and the else branch of
"if (bs == s || be == e)" will be taken, corrupting the management
structures.
Signed-off-by: Guillaume Knispel <gknispel@proformatique.com>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/lib/rheap.c

@@ -556,6 +556,7 @@ unsigned long rh_alloc_fixed(rh_info_t * info, unsigned long start, int size, co
 		be = blk->start + blk->size;
 		if (s >= bs && e <= be)
 			break;
+		blk = NULL;
 	}
 
 	if (blk == NULL)