qcacld-3.0: Remove unused WLAN_FEATURE_MBSSID macro

The Kbuild currently defines the macro WLAN_FEATURE_MBSSID.  However
this macro is not actually referenced in the driver, so remove it.

Change-Id: Id2254c298b5db2a18a75160d22904af3a6f90c06
CRs-Fixed: 2220916

Kbuild

@@ -1865,7 +1865,6 @@ CDEFINES :=	-DANI_LITTLE_BYTE_ENDIAN \
 		-DATH_SUPPORT_WAPI \
 		-DWLAN_FEATURE_LINK_LAYER_STATS \
 		-DFEATURE_WLAN_EXTSCAN \
-		-DWLAN_FEATURE_MBSSID \
 		-DCONFIG_160MHZ_SUPPORT \
 		-DCONFIG_MCL \
 		-DCONFIG_MCL_REGDB \
@@ -2312,9 +2311,6 @@ CDEFINES += -DFEATURE_WLAN_MCC_TO_SCC_SWITCH
 #enable wlan auto shutdown feature
 CDEFINES += -DFEATURE_WLAN_AUTO_SHUTDOWN
 
-#enable for MBSSID
-CDEFINES += -DWLAN_FEATURE_MBSSID
-
 #enable AP-AP ACS Optimization
 CDEFINES += -DFEATURE_WLAN_AP_AP_ACS_OPTIMIZE