[MIPS] Alchemy: Fix bunch of warnings

  CC      arch/mips/au1000/common/pci.o
arch/mips/au1000/common/pci.c:42: warning: large integer implicitly truncated to unsigned type
arch/mips/au1000/common/pci.c:43: warning: large integer implicitly truncated to unsigned type
arch/mips/au1000/common/pci.c:49: warning: large integer implicitly truncated to unsigned type
arch/mips/au1000/common/pci.c:50: warning: large integer implicitly truncated to unsigned type
arch/mips/au1000/common/pci.c: In function ‘au1x_pci_setup’:
arch/mips/au1000/common/pci.c:82: warning: ISO C90 forbids mixed declarations and code

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>