lib/vboot_kernel: Log speed at which kernel was loaded

This makes it easy to spot the speed at which the eMMC controller is
running.

vb2_load_partition: read 8419 KB in 48 ms at 174342 KB/s.

The calculation looks a little funky because I wanted to perform all
multiplications before the division to avoid losing any precision.

BRANCH=grunt
BUG=b:122244718
TEST=Verified it on grunt

Change-Id: I5fac584994bc478bfb27cbd4e2ea34af0be7f1d9
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1661366
Reviewed-by: Julius Werner <jwerner@chromium.org>
1 file changed