fpga: Migrate CONFIG_MAX_FPGA_DEVICES to Kconfig

This is always defined to 5, so use that as the default.

Cc: Michal Simek <michal.simek@amd.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Michal Simek <michal.simek@amd.com>
diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index 11b742e..4113de2 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -153,4 +153,9 @@
 	  This is a driver model based FPGA driver for sandbox.
 	  Currently it is a stub only, as there are no usable uclass methods yet.
 
+config MAX_FPGA_DEVICES
+	int "Maximum number of FPGA devices"
+	depends on FPGA
+	default 5
+
 endmenu