qcacld-3.0: Enable flag for increased Tx descs in QCA6390

Enable the increased tx descriptors flag for qca6390.
Based on 1Tx:8Rx NAN test case experiment, it requires
increase in Tx descriptors to burst trafficto each Rx device.

Change-Id: I7978732fda7149bf4c6ffaf4ea29f4e5dd30fd95
CRs-Fixed: 2665503

configs/default_defconfig

@@ -24,6 +24,7 @@ ifeq ($(CONFIG_CNSS_QCA6390), y)
 	CONFIG_WDI3_IPA_OVER_GSI :=y
 	CONFIG_DIRECT_BUF_RX_ENABLE := y
 	CONFIG_WMI_DBR_SUPPORT := y
+	CONFIG_MORE_TX_DESC := y
 endif
 
 ifeq ($(CONFIG_CNSS_QCA6490), y)