mt_scp/hrtimer: Fix race condition in timer_read_raw_system
mt_scp/hrtimer: Fix race condition in timer_read_raw_system

When the 32-bit bit timer @26Mhz wraps around, there is a short
amount of time when the 32-bit timer value (@1Mhz) is incorrect.

Fix this by manually adjusting sys_high if an interrupt is pending.

BRANCH=none
BUG=b:120173036
BUG=b:120763595
TEST=Boot kukui_scp, leave it running for 200 seconds
     taskinfo "time in exceptions" look reasonable

Change-Id: I053972d018e3e5e9c46cb73a0edb16b0354d5c43
Signed-off-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1372871
Commit-Ready: ChromeOS CL Exonerator Bot <fa429e5907f00867f797423aea74327bb02c91b6@appspot.gserviceaccount.com>
Reviewed-by: Yilun Lin <2f2733c7206ea2b76bd2db1905cc5e8a75841c48@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec