Convert CONFIG_BOOTP_DNS2 to Kconfig

This converts the following to Kconfig:
   CONFIG_BOOTP_DNS2
   CONFIG_BOOTP_PXE_CLIENTARCH

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/k2e_evm_defconfig b/configs/k2e_evm_defconfig
index 9f91fb9..aab8128 100644
--- a/configs/k2e_evm_defconfig
+++ b/configs/k2e_evm_defconfig
@@ -32,6 +32,7 @@
 # CONFIG_CMD_MMC is not set
 CONFIG_CMD_NAND=y
 # CONFIG_CMD_SETEXPR is not set
+CONFIG_BOOTP_DNS2=y
 CONFIG_MTDIDS_DEFAULT="nand0=davinci_nand.0"
 CONFIG_MTDPARTS_DEFAULT="mtdparts=davinci_nand.0:1024k(bootloader)ro,512k(params)ro,-(ubifs)"
 CONFIG_CMD_UBI=y