Convert CONFIG_HOSTNAME et al to Kconfig

This converts the following to Kconfig:
   CONFIG_GATEWAYIP
   CONFIG_HOSTNAME
   CONFIG_IPADDR
   CONFIG_NETMASK
   CONFIG_ROOTPATH
   CONFIG_SERVERIP
   CONFIG_UBOOTPATH

To do this, we introduce a CONFIG_USE_ form of each of the above and
change include/env_default.h to test for that to be set before setting a
value. Further, we don't want to stringify the IP address related values
as they are now properly strings via Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/integratorcp_cm1136_defconfig b/configs/integratorcp_cm1136_defconfig
index 7417b53..6d9d0e8 100644
--- a/configs/integratorcp_cm1136_defconfig
+++ b/configs/integratorcp_cm1136_defconfig
@@ -31,6 +31,10 @@
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_USE_BOOTFILE=y
 CONFIG_BOOTFILE="uImage"
+CONFIG_USE_IPADDR=y
+CONFIG_IPADDR="192.168.1.104"
+CONFIG_USE_SERVERIP=y
+CONFIG_SERVERIP="192.168.1.100"
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y