qcacld-3.0: Kbuild: Remove duplicate -DWLAN_FEATURE_GTK_OFFLOAD

Currently -DWLAN_FEATURE_GTK_OFFLOAD is being set twice, once
unconditionally and once based upon CONFIG_GTK_OFFLOAD. Since this is
properly featurized, remove the unconditional setting so that the
setting is correctly controlled by the configuration.

Change-Id: I6f820990dc48304f18f78ec59005c2188a677094
CRs-Fixed: 2223858

Kbuild

@@ -1860,7 +1860,6 @@ CDEFINES :=	-DANI_OS_TYPE_ANDROID=6 \
 		-DWLAN_FEATURE_PACKET_FILTERING \
 		-DWLAN_NS_OFFLOAD \
 		-DWLAN_SOFTAP_VSTA_FEATURE \
-		-DWLAN_FEATURE_GTK_OFFLOAD \
 		-DWLAN_WAKEUP_EVENTS \
 		-DFEATURE_WLAN_RA_FILTERING\
 		-DFEATURE_WLAN_LPHB \