snow: Return 0 from get_recovery_mode_from_vbnv.

This function isn't yet used for much, or perhaps anything, but where it
appears in the code it's ored with other values. Since we're not actually
retrieving anything, it might be best to return 0 so that the other values
that are being ored in can be expressed and this function can stay dormant
until it actually has something to do.

Change-Id: I6edc222a5c2d00ece2ecfad5191a615331eeaf16
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: http://review.coreboot.org/3098
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)

src/mainboard/google/snow/chromeos.c

@@ -116,5 +116,5 @@ int get_recovery_mode_switch(void)
 
 int get_recovery_mode_from_vbnv(void)
 {
-	return 1;
+	return 0;
 }