Simplify pci-ftpci100.c driver code and use new PCI_CONF1_ADDRESS() macro
for accessing PCI config space.

Link: https://lore.kernel.org/r/20220924092404.31776-3-pali@kernel.orgSigned-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lpieralisi@kernel.org>