Convert CONFIG_BOOTP_MAY_FAIL et al to Kconfig

This converts the following to Kconfig:
   CONFIG_BOOTP_MAY_FAIL
   CONFIG_BOOTP_VENDOREX
   CONFIG_BOOTP_BOOTFILESIZE
   CONFIG_BOOTP_NISDOMAIN
   CONFIG_BOOTP_TIMEOFFSET

Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/chromebook_coral_defconfig b/configs/chromebook_coral_defconfig
index c04b0dd..70d62c0 100644
--- a/configs/chromebook_coral_defconfig
+++ b/configs/chromebook_coral_defconfig
@@ -59,6 +59,7 @@
 CONFIG_CMD_SATA=y
 CONFIG_CMD_SPI=y
 CONFIG_CMD_USB=y
+CONFIG_BOOTP_BOOTFILESIZE=y
 CONFIG_CMD_TIME=y
 CONFIG_CMD_SOUND=y
 CONFIG_CMD_BOOTSTAGE=y