bcma: implement host code support for PCIe Gen 2 devices

This is stil incomplete, so we don't add PCI IDs of new devices yet.
Purpose of this patch is to allow testing & adjusting rest of the code.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>