PCI: designware: Simplify dw_pcie_cfg_read/write() interfaces

Callers of dw_pcie_cfg_read() and dw_pcie_cfg_write() previously had to
split the address into "addr" and "where".  The callees assumed "addr" was
32-bit aligned (with zeros in the low two bits) and they used only the low
two bits of "where".

Accept the entire address in "addr" and drop the now-redundant "where"
argument.  As an example, this replaces this:

  int dw_pcie_cfg_read(void __iomem *addr, int where, int size, u32 *val)
    *val = readb(addr + (where & 1));

with this:

  int dw_pcie_cfg_read(void __iomem *addr, int size, u32 *val)
    *val = readb(addr):

[bhelgaas: changelog, split access size change to separate patch]
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>