test: dm: pci: Add cases for finding PCI capability APIs

Add several PCI capability and extended capability ID registers
in the swap_case driver, so that we can add test case for
dm_pci_find_capability() and dm_pci_find_ext_capability().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>