scripts/Makefile.lib: Restore PCI related warnings to DTC_FLAGS

While we are working on correcting usage related to the pci_bridge and
pci_device_bus_num warnings, disable these flags for now.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index bfb5851..a819667 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -281,6 +281,10 @@
 	-Wno-avoid_unnecessary_addr_size \
 	-Wno-alias_paths \
 	-Wno-pci_device_reg
+
+# U-Boot specific disables
+DTC_FLAGS += -Wno-pci_bridge \
+        -Wno-pci_device_bus_num
 endif
 
 ifneq ($(findstring 2,$(KBUILD_ENABLE_EXTRA_GCC_CHECKS)),)