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/astro_mcf5373l_defconfig b/configs/astro_mcf5373l_defconfig
index d5e8430..c35222b 100644
--- a/configs/astro_mcf5373l_defconfig
+++ b/configs/astro_mcf5373l_defconfig
@@ -5,6 +5,7 @@
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="URMEL > "
 CONFIG_CMD_I2C=y
+CONFIG_CMD_FPGA_LOADMK=y
 # CONFIG_CMD_SETEXPR is not set
 # CONFIG_CMD_NET is not set
 # CONFIG_CMD_NFS is not set