Put VbDisplay* functions into their own file.

This refactoring will enable us to test and mock them separately from the
rest of the vboot_api functions.

BUG=chromium-os:17564
TEST=manual

Built for ARM, ran "vbexport_test display" at U-Boot prompt. Still works.

Change-Id: I2ddb01d3e981603f371aaa7317184457bdff48ac
Reviewed-on: http://gerrit.chromium.org/gerrit/6422
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Bill Richardson <wfrichar@chromium.org>
4 files changed