PCI: dwc: Fix inverted condition of DMA mask setup warning

Commit 660c486 ("PCI: dwc: Set 32-bit DMA mask for MSI target address
allocation") added dma_mask_set() call to explicitly set 32-bit DMA mask
for MSI message mapping, but for now it throws a warning on ret == 0, while
dma_set_mask() returns 0 in case of success.

Fix this by inverting the condition.

[bhelgaas: join string to make it greppable]
Fixes: 660c486 ("PCI: dwc: Set 32-bit DMA mask for MSI target address allocation")
Link: https://lore.kernel.org/r/20201222150708.67983-1-alobakin@pm.me
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -397,12 +397,8 @@ int dw_pcie_host_init(struct pcie_port *pp)
 							    pp);
 
 			ret = dma_set_mask(pci->dev, DMA_BIT_MASK(32));
-			if (!ret) {
-				dev_warn(pci->dev,
-					 "Failed to set DMA mask to 32-bit. "
-					 "Devices with only 32-bit MSI support"
-					 " may not work properly\n");
-			}
+			if (ret)
+				dev_warn(pci->dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n");
 
 			pp->msi_data = dma_map_single_attrs(pci->dev, &pp->msi_msg,
 						      sizeof(pp->msi_msg),