microblaze: Kconfig: introduce XILINX_MICROBLAZE0_FPGA_FAMILY option

Provide a static Kconfig value for the target FPGA archtitecture, as it is
done in Linux. The cpu-uclass driver will cross-check it with the value
read from PVR10 register.

Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
Link: https://lore.kernel.org/r/20220531181435.3473549-12-ovpanait@gmail.com


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