Add option to use Ada code in romstage

If selected, libgnat is linked into romstage. In addition, a call to
romstage_adainit() is added to support Ada program data
initialization.

BUG=b:252792591
BRANCH=firmware-brya-14505.B
TEST=Ada code compiles for romstage and loads successfully

Change-Id: I74f0460f6b14fde2b4bd6391e1782b2e5b217707
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70274
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Reviewed-by: Nick Vaccaro <nvaccaro@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/lib/Kconfig

@@ -5,6 +5,11 @@ config MISSING_BOARD_RESET
 	  implementation. This activates a stub that logs the missing
 	  board reset and halts execution.
 
+config ROMSTAGE_ADA
+	bool
+	help
+	  Selected by features that use Ada code in romstage.
+
 config RAMSTAGE_ADA
 	bool
 	help

src/lib/Makefile.inc

@@ -339,6 +339,7 @@ $(objcbfs)/%.debug.rmod: $(objcbfs)/%.debug | $(RMODTOOL)
 $(obj)/%.elf.rmod: $(obj)/%.elf | $(RMODTOOL)
 	$(RMODTOOL) -i $< -o $@
 
+romstage-$(CONFIG_ROMSTAGE_ADA) += cb.ads
 ramstage-$(CONFIG_RAMSTAGE_ADA) += cb.ads
 
 ifeq ($(CONFIG_RAMSTAGE_LIBHWBASE),y)

src/lib/gnat/Makefile.inc

@@ -51,6 +51,9 @@ $(foreach arch,$(standard-archs), \
 $(foreach arch,$(standard-archs), \
 	$(eval $(call libgnat-template,$(arch))))
 
+ifeq ($(CONFIG_ROMSTAGE_ADA),y)
+romstage-libs += $(obj)/libgnat-$(ARCH-romstage-y)/libgnat.a
+endif
 ifeq ($(CONFIG_RAMSTAGE_ADA),y)
 ramstage-libs += $(obj)/libgnat-$(ARCH-ramstage-y)/libgnat.a
 endif