powerpc/eeh: Replace pr_warning() with pr_warn()

pr_warn() is equal to pr_warning(), but the former is a bit more
formal according to commit fc62f2f ("kernel.h: add pr_warn for
symmetry to dev_warn, netdev_warn").

The patch replaces pr_warning() with pr_warn().

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/eeh_pe.c

@@ -179,7 +179,8 @@ void *eeh_pe_dev_traverse(struct eeh_pe *root,
 	void *ret;
 
 	if (!root) {
-		pr_warning("%s: Invalid PE %p\n", __func__, root);
+		pr_warn("%s: Invalid PE %p\n",
+			__func__, root);
 		return NULL;
 	}