cbfs/vboot: remove firmware component support

The Chrome OS verified boot path supported multiple CBFS
instances in the boot media as well as stand-alone assets
sitting in each vboot RW slot. Remove the support for the
stand-alone assets and always use CBFS accesses as the
way to retrieve data.

This is implemented by adding a cbfs_locator object which
is queried for locating the current CBFS. Additionally, it
is also signalled prior to when a program is about to be
loaded by coreboot for the subsequent stage/payload. This
provides the same opportunity as previous for vboot to
hook in and perform its logic.

BUG=chromium:445938
BRANCH=None
TEST=Built and ran on glados.
CQ-DEPEND=CL:307121,CL:31691,CL:31690

Change-Id: I6a3a15feb6edd355d6ec252c36b6f7885b383099
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/12689
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/include/cbfs.h

@@ -81,4 +81,18 @@ struct cbfs_props {
 /* Return < 0 on error otherwise props are filled out accordingly. */
 int cbfs_boot_region_properties(struct cbfs_props *props);
 
+/* Allow external logic to take action prior to locating a program
+ * (stage or payload). */
+void cbfs_prepare_program_locate(void);
+
+/* Object used to identify location of current cbfs to use for cbfs_boot_*
+ * operations. It's used by cbfs_boot_region_properties() and
+ * cbfs_prepare_program_locate(). */
+struct cbfs_locator {
+	const char *name;
+	void (*prepare)(void);
+	/* Returns 0 on successful fill of cbfs properties. */
+	int (*locate)(struct cbfs_props *props);
+};
+
 #endif