PCI: Make PCI_ROM_ADDRESS_MASK a 32-bit constant

A 64-bit value is not needed since a PCI ROM address consists in 32 bits.
This fixes a clang warning about "implicit conversion from 'unsigned long'
to 'u32'".

Also remove now unnecessary casts to u32 from __pci_read_base() and
pci_std_update_resource().

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index dfc9a279..7d5d4a5 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -231,7 +231,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 			res->flags |= IORESOURCE_ROM_ENABLE;
 		l64 = l & PCI_ROM_ADDRESS_MASK;
 		sz64 = sz & PCI_ROM_ADDRESS_MASK;
-		mask64 = (u32)PCI_ROM_ADDRESS_MASK;
+		mask64 = PCI_ROM_ADDRESS_MASK;
 	}
 
 	if (res->flags & IORESOURCE_MEM_64) {