defconfig: lahaina-gki: Enable USB Electrical and Link test support

Enable EHSET Test fixture driver to perform the high speed electrical
testing procedure for USB-IF compliance. Also enable the Link Layer
Test driver to allow for SuperSpeed link layer testing.

Change-Id: I3e54229c8b1626cd3027373f269297843a2bd0eb
Signed-off-by: Jack Pham <jackp@codeaurora.org>