ia64: Skip zero-length resources in PCI root bridge _CRS. This fixes

ia64: Skip zero-length resources in PCI root bridge _CRS.  This fixes
some ugly messages that used to show up on Tiger and other Intel
boxes:

        alloc 0xffffffff-0x0 from PCI mem for PCI Bus 0000:02 failed
        alloc 0xffffffff-0x0 from PCI mem for PCI Bus 0000:08 failed
        alloc 0xffffffff-0x0 from PCI mem for PCI Bus 0000:08 failed
        alloc 0xffffffff-0x0 from PCI mem for PCI Bus 0000:08 failed
        alloc 0xffff-0x0 from PCI IO for PCI Bus 0000:08 failed
        alloc 0xffffffff-0x0 from PCI mem for PCI Bus 0000:09 failed
        alloc 0xffffffff-0x0 from PCI mem for PCI Bus 0000:0f failed