qcacld-3.0: Fix wlan_cfg header file inclusion issue

wlan_cfg.h header file was not getting included due to error in the
wlan_cfg path.

Change-Id: I97d706f1c35475e4da4be3d181f2d6c215b531cc
CRs-Fixed: 2005582

Kbuild

@@ -953,9 +953,10 @@ DP_OBJS := $(DP_SRC)/dp_main.o \
 endif
 
 ############ CFG ############
-WCFG_DIR := $(WLAN_COMMON_ROOT)/wlan_cfg
-WCFG_INC := -I$(WCFG_DIR)
-WCFG_OBJS := $(WCFG_DIR)/wlan_cfg.o
+WCFG_DIR := wlan_cfg
+WCFG_INC := -I$(WLAN_COMMON_INC)/$(WCFG_DIR)
+WCFG_SRC := $(WLAN_COMMON_ROOT)/$(WCFG_DIR)
+WCFG_OBJS := $(WCFG_SRC)/wlan_cfg.o
 
 ############ OL ############
 OL_DIR :=     core/dp/ol