qcacld-3.0: Fix DHCP_SERVER_OFFLOAD featurization

When the DHCP_SERVER_OFFLOAD feature is enabled the driver does not
build, so address the build issues.

Change-Id: I42103afd91c4bed2d04f22bdb6159e286ff12fa0
CRs-Fixed: 2399937
diff --git a/Kbuild b/Kbuild
index 59b3f40..6459bf1 100644
--- a/Kbuild
+++ b/Kbuild
@@ -1917,6 +1917,7 @@
 cppflags-$(CONFIG_SOFTAP_CHANNEL_RANGE) += -DSOFTAP_CHANNEL_RANGE
 cppflags-$(CONFIG_FEATURE_WLAN_SCAN_PNO) += -DFEATURE_WLAN_SCAN_PNO
 cppflags-$(CONFIG_WLAN_FEATURE_PACKET_FILTERING) += -DWLAN_FEATURE_PACKET_FILTERING
+cppflags-$(CONFIG_DHCP_SERVER_OFFLOAD) += -DDHCP_SERVER_OFFLOAD
 cppflags-$(CONFIG_WLAN_NS_OFFLOAD) += -DWLAN_NS_OFFLOAD
 cppflags-$(CONFIG_FEATURE_WLAN_RA_FILTERING) += -DFEATURE_WLAN_RA_FILTERING
 cppflags-$(CONFIG_FEATURE_WLAN_LPHB) += -DFEATURE_WLAN_LPHB