s390/pci: cleanup clp page allocation

Use the __get_free_pages wrapper in clp_alloc_block. Also change the
allocation to use one page only. This page is used as CLP response
block e.g. to list available pci functions. Using one page we can
list > 250 pci functions at once and we have code to loop around this
CLP command (if not all functions fit into to the CLP block) already
in place.

Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/pci/pci_clp.c b/arch/s390/pci/pci_clp.c
index 702bd26..f339fe2f 100644
--- a/arch/s390/pci/pci_clp.c
+++ b/arch/s390/pci/pci_clp.c
@@ -37,8 +37,7 @@
 
 static void *clp_alloc_block(void)
 {
-	struct page *page = alloc_pages(GFP_KERNEL, get_order(CLP_BLK_SIZE));
-	return (page) ? page_address(page) : NULL;
+	return (void *) __get_free_pages(GFP_KERNEL, get_order(CLP_BLK_SIZE));
 }
 
 static void clp_free_block(void *ptr)