fpga: dfl: pci: add irq info for feature devices enumeration

Some DFL FPGA PCIe cards (e.g. Intel FPGA Programmable Acceleration
Card) support MSI-X based interrupts. This patch allows PCIe driver
to prepare and pass interrupt resources to DFL via enumeration API.
These interrupt resources could then be assigned to actual features
which use them.

Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>