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/mt_ventoux_defconfig b/configs/mt_ventoux_defconfig
index e426772..c4a6f20 100644
--- a/configs/mt_ventoux_defconfig
+++ b/configs/mt_ventoux_defconfig
@@ -17,6 +17,7 @@
 CONFIG_CMD_MMC=y
 CONFIG_CMD_I2C=y
 CONFIG_CMD_USB=y
+CONFIG_CMD_FPGA_LOADMK=y
 CONFIG_CMD_GPIO=y
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_DHCP=y