qcacld-3.0: Modify Kbuild to add new beacon header file

In wmi new file, wmi_unified_bcn_api.c is added.
Add this file in Kbuild.

Change-Id: I4fdbf041b53b5f1606d324714f01088742a9307f
CRs-Fixed: 2366772
diff --git a/Kbuild b/Kbuild
index bbe1f0e..8519c93 100644
--- a/Kbuild
+++ b/Kbuild
@@ -1136,6 +1136,10 @@
 WMI_OBJS += $(WMI_OBJ_DIR)/wmi_unified_sta_tlv.o
 endif
 
+ifeq ($(CONFIG_WMI_BCN_OFFLOAD), y)
+WMI_OBJS += $(WMI_OBJ_DIR)/wmi_unified_bcn_api.o
+endif
+
 ########### FWLOG ###########
 FWLOG_DIR := $(WLAN_COMMON_ROOT)/utils/fwlog