[POWERPC] Fix a compile warning in pci_32.c

__must_check, so do so.

Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/pci_32.c b/arch/powerpc/kernel/pci_32.c
index cd35c96..04a3109 100644
--- a/arch/powerpc/kernel/pci_32.c
+++ b/arch/powerpc/kernel/pci_32.c
@@ -581,8 +581,11 @@
 			if ((r->flags & IORESOURCE_UNSET) && r->end &&
 			    (!ppc_md.pcibios_enable_device_hook ||
 			     !ppc_md.pcibios_enable_device_hook(dev, 1))) {
+				int rc;
+
 				r->flags &= ~IORESOURCE_UNSET;
-				pci_assign_resource(dev, idx);
+				rc = pci_assign_resource(dev, idx);
+				BUG_ON(rc);
 			}
 		}