kbuild: disable dtc simple_bus_reg warnings by default

[ Upstream commit 70523a3ce5ff928faa43bb2cad554dc63438e3e7 ]

The updated version of dtc has a bug fix for simple_bus_reg warnings
and lots of warnings are generated now. So disable this warning by
default.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>

scripts/Makefile.lib

@@ -252,6 +252,7 @@ DTC_FLAGS += -Wno-unit_address_vs_reg \
 	-Wno-alias_paths \
 	-Wno-graph_child_address \
 	-Wno-graph_port \
+	-Wno-simple_bus_reg \
 	-Wno-unique_unit_address \
 	-Wno-pci_device_reg
 endif