Relax allocations requirements

CAS does not need atomic alocations virtually anywhere. GFP_NOIO
should be sufficient in IO path. When allocation buffers during
module initialization use GFP_KERNEL.

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>

modules/cas_cache/context.c

@@ -55,7 +55,7 @@ void *_cas_alloc_page_rpool(void *allocator_ctx, int cpu)
 {
 	struct page *page;
 
-	page = alloc_page(GFP_NOIO | __GFP_NORETRY);
+	page = alloc_page(GFP_KERNEL);
 	if (!page)
 		return NULL;