spi: dw-pci: apply pci_bar and re-use pci_name

Nevertheless pci_bar is 0 let's explicitly use it when map IO regions. While
here, use pci_name instead of dev_name.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>