libusb: remove forced GCC usage.

libusb seems to be working correctly with ToT clang in Chrome OS
so remove the forced GCC workaround.

BUG=chromium:723145, chromium:979914
TEST=rebuild libusb in sdk; cros_sdk --no-ns-pid ; sudo servod

Change-Id: If7bea2349ddce2bc5f89c6b84e7f71d29e0e7718
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/2595672
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: YH Lin <yueherngl@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
2 files changed