Kbuild: enable -Wunused-macros warning for "make W=2"

We have lots of dead defines and macros in drivers, lets offer users a way
to detect and eventually remove them.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

authored by

Johannes Thumshirn and committed by
Masahiro Yamada
de8cf950 8e9b4667

+1
+1
scripts/Makefile.extrawarn
··· 37 37 warning-2 += $(call cc-option, -Wmissing-field-initializers) 38 38 warning-2 += $(call cc-option, -Wsign-compare) 39 39 warning-2 += $(call cc-option, -Wmaybe-uninitialized) 40 + warning-2 += $(call cc-option, -Wunused-macros) 40 41 41 42 warning-3 := -Wbad-function-cast 42 43 warning-3 += -Wcast-qual