qcacld-3.0: enable QCA_WIFI_QCA6290_11AX_MU_UL feature flag

Enable QCA_WIFI_QCA6290_11AX_MU_UL feature flag for HAL layer.

Change-Id: Ia9cd4e0638fa4f340145f9523af14f720df198f8

Kbuild

@@ -2519,7 +2519,7 @@ ccflags-$(CONFIG_HIF_PCI) += -DCE_SVC_CMN_INIT
 ccflags-$(CONFIG_HIF_SNOC) += -DCE_SVC_CMN_INIT
 
 ifeq ($(CONFIG_QCA6290_11AX), y)
-cppflags-y += -DQCA_WIFI_QCA6290_11AX
+cppflags-y += -DQCA_WIFI_QCA6290_11AX -DQCA_WIFI_QCA6290_11AX_MU_UL
 endif
 
 ifeq ($(CONFIG_LITHIUM), y)