device: include devicetree in bootblock stage

Allow bootblock to get access to the static device tree like
other early stages. device_romstage.c was renamed to
device_simple.c to better articulate the usage since it's not
just being used in romstage.

BUG=chrome-os-partner:55357

Change-Id: I3d63d2754c737cc738c09a3e3b3b468362fb78d1
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/15837
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Subrata Banik <subrata.banik@intel.com>
Tested-by: build bot (Jenkins)
diff --git a/src/device/Makefile.inc b/src/device/Makefile.inc
index 261ed53..232a981 100644
--- a/src/device/Makefile.inc
+++ b/src/device/Makefile.inc
@@ -20,8 +20,9 @@
 ramstage-srcs += src/mainboard/$(MAINBOARDDIR)/hda_verb.c
 endif
 
-verstage-y += device_romstage.c
-romstage-y += device_romstage.c
+bootblock-y += device_simple.c
+verstage-y += device_simple.c
+romstage-y += device_simple.c
 romstage-$(CONFIG_PCI) += pci_early.c
 
 subdirs-y += oprom dram