qcacld-3.0: Kbuild: Remove duplicate -W switches

Currently the Kbuild adds "-Wall -Werror" to the C command line.
However, the kernel already adds these by default, so stop adding the
duplicates.

Change-Id: I8d0b777feafd726ab29278739ac20bcaf0f7f000
CRs-Fixed: 3463791

Kbuild

@@ -3239,7 +3239,6 @@ INCS +=		$(COAP_WMI_INC)
 
 ccflags-y += $(INCS)
 
-cppflags-y += -Wall -Werror
 cppflags-y += -include $(WLAN_ROOT)/configs/default_config.h
 
 # CFG80211_MLO_KEY_OPERATION_SUPPORT