CRAS/libcras: Fix unit test error in arm

`libc::off_t` has different types on different architectures.
The test should use `libc::off_t` directly.

Test unit tests of libcras in different architectures.

BUG=chromium:907520
TEST=$ FEATURES=test emrege-{eve,kevin} libcras

Change-Id: If8a5099e0c7f80c7a828590346b0df6f72ae540e
Reviewed-on: https://chromium-review.googlesource.com/1433172
Commit-Ready: Chih-Yang Hsia <paulhsia@chromium.org>
Tested-by: Chih-Yang Hsia <paulhsia@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
1 file changed