dtc: turn off dtc unit address warnings by default

The newly added dtc warning to check DT unit-address without reg
property and vice-versa generates lots of warnings. Turn off the check
unless building with W=1 or W=2.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: linux-kbuild@vger.kernel.org

scripts/Makefile.lib

@@ -277,6 +277,11 @@ cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \
 # ---------------------------------------------------------------------------
 DTC ?= $(objtree)/scripts/dtc/dtc
 
+# Disable noisy checks by default
+ifeq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
+DTC_FLAGS += -Wno-unit_address_vs_reg
+endif
+
 # Generate an assembly file to wrap the output of the device tree compiler
 quiet_cmd_dt_S_dtb= DTB     $@
 cmd_dt_S_dtb=						\