usb/xhci: Add support for EHSET tests for host compliance

USB 2.0 specification defines following test modes for host electrical
compliance: TEST_J/K/SE0_NAK and TEST_PACKET. Hence add support for
same.

CRs-Fixed: 868394
Change-Id: I885ae66be2d8cca17bcc0b87b7635a71c734e4b2
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
Signed-off-by: Mayank Rana <mrana@codeaurora.org>