qcacld-3.0: Do not reset CONFIG_IPA3 if target is QCA6390

Do not reset CONFIG_IPA3 if target is QCA6390 to avoid mismatch between
Kbuild & qca6390_defconfig.

Change-Id: Iffe2976576a653a145a15cf798737569be116ec3
CRs-Fixed: 2946663

configs/qca6390_defconfig

@@ -11,7 +11,6 @@ ifeq ($(CONFIG_CNSS_QCA6390), y)
 	CONFIG_LITHIUM := y
 	CONFIG_WLAN_FEATURE_11AX := y
 	CONFIG_WLAN_FEATURE_DFS_OFFLOAD := y
-	CONFIG_IPA3 := n
 	CONFIG_SCALE_INCLUDES := y
 	CONFIG_MORE_TX_DESC := y
 	CONFIG_FW_THERMAL_THROTTLE := y