replace APP_xxDHCPxx with xxDHCPxx, it's more consistent with the rest

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/scripts/defconfig b/scripts/defconfig
index f8a92d4..a98c7b6 100644
--- a/scripts/defconfig
+++ b/scripts/defconfig
@@ -744,12 +744,12 @@
 CONFIG_FEATURE_TRACEROUTE_VERBOSE=y
 # CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE is not set
 # CONFIG_FEATURE_TRACEROUTE_USE_ICMP is not set
-CONFIG_APP_UDHCPD=y
-CONFIG_APP_DHCPRELAY=y
-CONFIG_APP_DUMPLEASES=y
+CONFIG_UDHCPD=y
+CONFIG_DHCPRELAY=y
+CONFIG_DUMPLEASES=y
 CONFIG_FEATURE_UDHCPD_WRITE_LEASES_EARLY=y
 CONFIG_DHCPD_LEASES_FILE="/var/lib/misc/udhcpd.leases"
-CONFIG_APP_UDHCPC=y
+CONFIG_UDHCPC=y
 CONFIG_FEATURE_UDHCPC_ARPING=y
 CONFIG_FEATURE_UDHCP_PORT=y
 CONFIG_UDHCP_DEBUG=9