gbmcweb: Fix SRCREV The SRCREV was broken. Fixing it with lataest from 26.24.x gbmcweb release branch. Tested: fusion2 N/A Platforms-Affected: TTF Google-Bug-Id: 527471596 Google-Bug-Id: 525098495 Change-Id: I1ef115f54eeb36b11f2da404482f523ee9ad2de9 Signed-off-by: Edward Lee <edwarddl@google.com>