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/cpu/intel/car/romstage.c

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <adainit.h>
 #include <arch/romstage.h>
 #include <arch/symbols.h>
 #include <commonlib/helpers.h>
@@ -40,6 +41,18 @@ void __noreturn romstage_main(void)
 	if (CONFIG(VBOOT_EARLY_EC_SYNC))
 		vboot_sync_ec();
 
+	/*
+	 * We can generally jump between C and Ada code back and forth
+	 * without trouble. But since we don't have an Ada main() we
+	 * have to do some Ada package initializations that GNAT would
+	 * do there. This has to be done before calling any Ada code.
+	 *
+	 * The package initializations should not have any dependen-
+	 * cies on C code. So we can call them here early, and don't
+	 * have to worry at which point we can start to use Ada.
+	 */
+	romstage_adainit();
+
 	mainboard_romstage_entry();
 
 	/* Check the stack. */