Be aggressive in saving locale to nvram.

On x86 platforms, the power button and lid switch events have to be handled
by coreboot SMM code, because it needs to interact with the southbridge
and/or EC, and U-Boot doesn't have a way to do that. Once the kernel takes
over, it sends an SMI to that code which tells it to start delivering ACPI
events instead of whatever pre-ACPI handling it has been doing.

U-Boot doesn't have any code to handle either case, and adding it would
either be a major undertaking (adding ACPI support to U-Boot!), or would
require creating yet another special-purpose interface just for our U-Boot
(yuck).

It's much simpler to just make vboot_reference be more aggressive about
writing to the nvram for this one case where it matters.

OTOH, ARM will need U-Boot to handle the lid switch and power button via
GPIOs since it uses only U-Boot and has no SMI handler. This change isn't
necessary for ARM, but shouldn't hurt either.

BUG=chrome-os-partner:7689
TEST=manual

1. Boot to dev-mode screen or recovery screen.
2. Press arrow keys to change locale.
3. Power off (press power button or yank A/C & battery)
4. Power on again.

The BIOS screen locale should still be set to your last choice before
powering off.

Change-Id: I9008811c3be71de47ff1c6899e81955cf0560a52
Reviewed-on: https://gerrit.chromium.org/gerrit/14721
Tested-by: Bill Richardson <wfrichar@chromium.org>
Commit-Ready: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

firmware/lib/vboot_api_kernel.c

@@ -127,8 +127,11 @@ VbError_t VbBootDeveloper(VbCommonParams* cparams, LoadKernelParams* p) {
   do {
     uint32_t key;
 
-    if (VbExIsShutdownRequested())
+    if (VbExIsShutdownRequested()) {
+      VBDEBUG(("VbBootDeveloper() - shutdown is requested!\n"));
+      VbAudioClose(audio);
       return VBERROR_SHUTDOWN_REQUESTED;
+    }
 
     key = VbExKeyboardRead();
     switch (key) {