And convert grub_acpi_find_fadt() to use it.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
PIT isn't available on some of new hardware including Hyper-V. So
use pmtimer for calibration. Moreover pmtimer calibration is faster, so
use it on coreboor where booting time is important.
Based on patch by Michael Chang.
