[POWERPC] Make rheap safe for spinlocks

The rheap allocation function, rh_alloc, could call kmalloc with GFP_KERNEL.
This can sleep, which means you couldn't hold a spinlock while called rh_alloc.
Change all kmalloc calls to use GFP_ATOMIC so that it won't sleep.  This is
safe because only small blocks are allocated.
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/lib/rheap.c

@@ -54,7 +54,7 @@ static int grow(rh_info_t * info, int max_blocks)
 
 	new_blocks = max_blocks - info->max_blocks;
 
-	block = kmalloc(sizeof(rh_block_t) * max_blocks, GFP_KERNEL);
+	block = kmalloc(sizeof(rh_block_t) * max_blocks, GFP_ATOMIC);
 	if (block == NULL)
 		return -ENOMEM;
 
@@ -258,7 +258,7 @@ rh_info_t *rh_create(unsigned int alignment)
 	if ((alignment & (alignment - 1)) != 0)
 		return ERR_PTR(-EINVAL);
 
-	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	info = kmalloc(sizeof(*info), GFP_ATOMIC);
 	if (info == NULL)
 		return ERR_PTR(-ENOMEM);