Revert "xhci: Add a flag to disable USB3 lpm on a xhci root port level."

This reverts commit 30f9ad9f which is
commit 0522b9a1653048440da5f21747f21e498b9220d1 upstream.

It breaks the Android ABI for the xhci pci driver, for an issue that is
not needed in this Android branch.  If it is needed, it can come back in
the future in a way that preserves the ABI.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ic580277efe436b17df5b4a4c4b3858b12fbd5532