security/vboot: Removed vboot_prepare from vboot_locator

When prog_locate() is called in the stage VBOOT is starting from and the
image to be loaded is not the target image vboot_prepare() may be called
too early.

To prevent this vboot_prepare() is removed from the vboot_locator
structure. This allows more control over the start of the vboot logic.

To clarify the change the vboot_prepare() has been renamed to
vboot_run_logic() and calls to initialize vboot have been added at the
following places:

postcar_loader: when VBOOT starts in ROMSTAGE
romstage_loader: when VBOOT starts in BOOTBLOCK
ramstage_loader: when VBOOT starts in ROMSTAGE

BUG=N/A
TEST=tested on facebook fbg1701

Change-Id: Id5e8fd78458c09dd3896bfd142bd49c2c3d686df
Signed-off-by: Wim Vervoorn <wvervoorn@eltan.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36543
Reviewed-by: Frans Hendriks <fhendriks@eltan.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/arch/x86/postcar_loader.c

@@ -23,6 +23,7 @@
 #include <romstage_handoff.h>
 #include <stage_cache.h>
 #include <timestamp.h>
+#include <security/vboot/vboot_common.h>
 
 static inline void stack_push(struct postcar_frame *pcf, uint32_t val)
 {
@@ -171,6 +172,8 @@ static void load_postcar_cbfs(struct prog *prog, struct postcar_frame *pcf)
 		.prog = prog,
 	};
 
+	vboot_run_logic();
+
 	if (prog_locate(prog))
 		die_with_post_code(POST_INVALID_ROM,
 				   "Failed to locate after CAR program.\n");