CHROMIUM: iwl7000: Temporarily disable fall through warning.

Clang/GCC disagree on how to handle fall-through
especially on handling the fall through comment in code.
Temporarily disable it in the iwl7000 drivers.

GCC 4.9.2 used in Chrome OS does not support this warning
so any coverage loss should be minimal.

Details: ClangBuiltLinux/linux#636

BUG=chromium:997991
TEST=kernel compiles with ToT clang.

Signed-off-by: Manoj Gupta <manojgupta@google.com>
Change-Id: I079e40f3c9282238dd1e4cb964976232fbe971a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1792417
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Tested-by: Manoj Gupta <manojgupta@chromium.org>

drivers/net/wireless/iwl7000/iwlwifi/Makefile

@@ -31,7 +31,9 @@ iwlwifi-$(CPTCFG_IWLWIFI_DEVICE_TESTMODE) += iwl-tm-gnl.o iwl-dnt-cfg.o iwl-dnt-
 iwlwifi-$(CPTCFG_IWLWIFI_DEVICE_TESTMODE) += iwl-dnt-dev-if.o fw/testmode.o
 
 ccflags-y += -I$(src)
-subdir-ccflags-y += $(call cc-option,-Wimplicit-fallthrough)
+# Re-enable -Wimplicit-fallthrough after clang/gcc disagreements are resolved.
+# https://crbug.com/997991.
+# subdir-ccflags-y += $(call cc-option,-Wimplicit-fallthrough)
 
 obj-$(CPTCFG_IWLMVM)	+= mvm/
 obj-$(CPTCFG_IWLXVT)	+= xvt/

drivers/net/wireless/iwl7000/mac80211/Makefile

@@ -54,7 +54,9 @@ mac80211-y += bucket_locks.o
 mac80211-y += rhashtable.o
 
 CFLAGS_trace.o := -I$(src)
-subdir-ccflags-y += $(call cc-option,-Wimplicit-fallthrough)
+# Re-enable -Wimplicit-fallthrough after clang/gcc disagreements are resolved.
+# https://crbug.com/997991.
+# subdir-ccflags-y += $(call cc-option,-Wimplicit-fallthrough)
 
 CFLAGS_tx.o += -include "hdrs/iwl-tx.h"
 CFLAGS_debugfs.o += -include "hdrs/net/fq.h"