vboot: update VbExNvStorageWrite function

Going forwards, vb2ex_commit_data will be used to flush both
nvdata and secdata.

The patch that is circularly dependent on this lies between a patch that
makes vboot no longer build and the patch that fixes that, so we have to
pull the whole thing in at once to sort out the mess.

Updating from commit id 1c4dbaa0:
2019-11-18 Julius Werner   Makefile: Fix typo for MOCK_TPM

to commit id 695c56dc:
2019-12-04 Julius Werner   Makefile: Make loop unrolling fully
                           controllable by the caller

BUG=b:124141368, chromium:1006689
TEST=make clean && make test-abuild
BRANCH=none

Change-Id: Ia2612da0df101cd3c46151dbce728633a39fada1
Signed-off-by: Joel Kitching <kitching@google.com>
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37315
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

3rdparty/vboot

@@ -1 +1 @@
-Subproject commit 1c4dbaa08419e13366db32ed20244f63c34388a0
+Subproject commit 695c56dc50a59e5c9098c94f41b3d86b8f99baf1

src/security/vboot/ec_sync.c

@@ -399,9 +399,9 @@ vb2_error_t VbExDisplayScreen(uint32_t screen_type, uint32_t locale,
 /*
  * Write opaque data into NV storage region.
  */
-vb2_error_t VbExNvStorageWrite(const uint8_t *buf)
+vb2_error_t vb2ex_commit_data(struct vb2_context *ctx)
 {
-	save_vbnv(buf);
+	save_vbnv(ctx->nvdata);
 	return VB2_SUCCESS;
 }