floss: fix TimeDelta calls from older libchrome breaks CrOS build.

base::TimeDelta calls introduced to eatt are only for libchrome before
version 931007. Therefore, call to it break the updated ChromeOS build.

BUG: 239467279
Tag: #floss
Test: emerge-${BOARD} floss
Change-Id: I2a375f6624f12a883f1e177d581285f44d459f82