arm_fpga: Support more CPU clusters

The maximum number of clusters is currently set to 2, which is quite
limiting. As there are FPGA images with 4 clusters, let's increase the
limit to 4.

Change-Id: I9a85ca07ebbd2a018ad9668536d867ad6b75e537
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
1 file changed