qcacld-3.0: Enable -Wheader-guard compiler option

This is a qcacld-2.0 to qcacld-3.0 propagation.

Enable the compiler's -Wheader-guard switch. This will help
catch mismatches between #ifndef and #define lines in header guard.

Change-Id: Ic05a829eadbf974598370c494a5cff10201ec600
CRs-Fixed: 1091052

Kbuild

@@ -1665,6 +1665,10 @@ EXTRA_CFLAGS += -Wframe-larger-than=4096
 endif
 endif
 
+ifeq ($(call cc-option-yn, -Wheader-guard),y)
+EXTRA_CFLAGS += -Wheader-guard
+endif
+
 # Module information used by KBuild framework
 obj-$(CONFIG_QCA_CLD_WLAN) += $(MODNAME).o
 $(MODNAME)-y := $(OBJS)