Improve configuration of FPGA subsystem

This patch removes the FPGA subsystem configuration through
the CONFIG_FPGA bitmask configuration option.

See README for the new options:

	CONFIG_FPGA,
	CONFIG_FPGA_<vendor>,
	CONFIG_FPGA_<family>

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd-electronics.com>
diff --git a/include/configs/GEN860T.h b/include/configs/GEN860T.h
index bfbf3a8..3eb3131 100644
--- a/include/configs/GEN860T.h
+++ b/include/configs/GEN860T.h
@@ -273,7 +273,9 @@
  * Virtex2 FPGA configuration support
  */
 #define CONFIG_FPGA_COUNT		1
-#define CONFIG_FPGA				CFG_XILINX_VIRTEX2
+#define CONFIG_FPGA
+#define CONFIG_FPGA_XILINX
+#define CONFIG_FPGA_VIRTEX2
 #define CFG_FPGA_PROG_FEEDBACK