bootstat write timing to the kernel.

BUG=chromium-os:19176
TEST=Test it on ChromeOS, and /sys/kernel/debug/bootstat/report contains
all timings written by bootstat.

Change-Id: I25a2e0aec1b24f52047c7bc97f0ad40f78009a8b
Reviewed-on: http://gerrit.chromium.org/gerrit/6598
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Da Zheng <zhengda@chromium.org>
1 file changed