kbuild: Enable dtc 'unit_address_format' warning by default

With all the 'unit_address_format' warnings fixed, enable the warning by
default.

Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-kbuild@vger.kernel.org
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20210913192816.1225025-9-robh@kernel.org

scripts/Makefile.lib

@@ -310,7 +310,6 @@ DTC_FLAGS += -Wno-interrupt_provider
 # Disable noisy checks by default
 ifeq ($(findstring 1,$(KBUILD_EXTRA_WARN)),)
 DTC_FLAGS += -Wno-unit_address_vs_reg \
-	-Wno-unit_address_format \
 	-Wno-avoid_unnecessary_addr_size \
 	-Wno-alias_paths \
 	-Wno-graph_child_address \