CRAS: util - Expand cras_frames_since_time return value to uint64_t

The original type unsigned integer might overflow when time period is
longer than 25 hours (60 * 60 * 25 * 48000 > 2 ^ 32). Using uint64_t
instead can support long enough time.

BUG=none
TEST=Bluetooth won't be broken after playing for a long time.

Change-Id: I608dd022f7653e27e5e20300d103270c9171090d
Reviewed-on: https://chromium-review.googlesource.com/1314273
Commit-Ready: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Tested-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
2 files changed