fpga: xilinx: add bitstream flags to driver desc

Store a set of supported bitstream types in xilinx_desc structure.
It will be used to determine whether an FPGA image is able to be
loaded with a given driver.

Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@foundries.io>
Tested-by: Ricardo Salveti <ricardo@foundries.io>
Tested-by: Adrian Fiergolski <adrian.fiergolski@fastree3d.com>
Link: https://lore.kernel.org/r/20220722141614.297383-4-oleksandr.suvorov@foundries.io


Signed-off-by: Michal Simek <michal.simek@amd.com>