PCI: dwc: Fix 'cast truncates bits from constant value'

Fixes warning given by executing "make C=2 drivers/pci/"

Sparse output:
CHECK drivers/pci/controller/dwc/pcie-designware.c
 drivers/pci/controller/dwc/pcie-designware.c:432:52: warning:
 cast truncates bits from constant value (ffffffff7fffffff becomes
 7fffffff)

Link: https://lore.kernel.org/r/7ea7f7d342f97c758949a17b870012f52ce5b3f5.1600767645.git.gustavo.pimentel@synopsys.comReported-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Joao Pinto <jpinto@synopsys.com>

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

@@ -452,7 +452,7 @@ void dw_pcie_disable_atu(struct dw_pcie *pci, int index,
 	}
 
 	dw_pcie_writel_dbi(pci, PCIE_ATU_VIEWPORT, region | index);
-	dw_pcie_writel_dbi(pci, PCIE_ATU_CR2, (u32)~PCIE_ATU_ENABLE);
+	dw_pcie_writel_dbi(pci, PCIE_ATU_CR2, ~(u32)PCIE_ATU_ENABLE);
 }
 
 int dw_pcie_wait_for_link(struct dw_pcie *pci)