powerpc/powernv/npu: Fix debugfs_simple_attr.cocci warnings

Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE
for debugfs files.

Semantic patch information:
Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file()
imposes some significant overhead as compared to
DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe().

Generated by: scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1545705876-63132-1-git-send-email-yuehaibing@huawei.com

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -3086,8 +3086,8 @@ static int pnv_pci_diag_data_set(void *data, u64 val)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(pnv_pci_diag_data_fops, NULL,
-			pnv_pci_diag_data_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(pnv_pci_diag_data_fops, NULL, pnv_pci_diag_data_set,
+			 "%llu\n");
 
 #endif /* CONFIG_DEBUG_FS */
 
@@ -3112,8 +3112,8 @@ static void pnv_pci_ioda_create_dbgfs(void)
 			continue;
 		}
 
-		debugfs_create_file("dump_diag_regs", 0200, phb->dbgfs, hose,
-				    &pnv_pci_diag_data_fops);
+		debugfs_create_file_unsafe("dump_diag_regs", 0200, phb->dbgfs,
+					   hose, &pnv_pci_diag_data_fops);
 	}
 #endif /* CONFIG_DEBUG_FS */
 }