libpayload: usb: Remove generic roothub reset port function

The generic roothub reset port function is overly broad and does some
things which may be undesirable, such as issuing multiple resets to a
port if the reset is deemed to have finished too quickly. Remove the
generic function and replace it with a controller-specific function,
currently only implemented for xhci.

BUG=chrome-os-partner:24090
TEST=Manual on Rambi. Verify that USB 3.0 media is found + bootable on
cold boot.
BRANCH=Rambi.

Change-Id: Id46f73ea3341d4d01d2b517c6bf687402022d272
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/189495
Reviewed-by: Julius Werner <jwerner@chromium.org>
3 files changed