performance: Update link to bootperf document.

BUG=None
TEST=open the link in browser.

Change-Id: I0902f9372eb65c063966b76060392dc4665d8620
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/5475623
Tested-by: Junichi Uekawa <uekawa@chromium.org>
Reviewed-by: Chinglin Yu <chinglinyu@chromium.org>
Commit-Queue: Junichi Uekawa <uekawa@chromium.org>
Reviewed-by: Morg <morg@google.com>
1 file changed