Convert CONFIG_CMD_FPGA_LOADBP et al to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_FPGA_LOADBP
   CONFIG_CMD_FPGA_LOADFS
   CONFIG_CMD_FPGA_LOADMK
   CONFIG_CMD_FPGA_LOADP

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/zynq_picozed_defconfig b/configs/zynq_picozed_defconfig
index 3c3a5b2..7ca69a9 100644
--- a/configs/zynq_picozed_defconfig
+++ b/configs/zynq_picozed_defconfig
@@ -12,6 +12,10 @@
 CONFIG_CMD_MMC=y
 CONFIG_CMD_USB=y
 CONFIG_CMD_DFU=y
+CONFIG_CMD_FPGA_LOADBP=y
+CONFIG_CMD_FPGA_LOADFS=y
+CONFIG_CMD_FPGA_LOADMK=y
+CONFIG_CMD_FPGA_LOADP=y
 CONFIG_CMD_GPIO=y
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_TFTPPUT=y