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

This reverts commit 4d70a8a9 which is
commit 0522b9a1 upstream.

It breaks the android kernel abi and is not needed for android at this
point in time as the USB3 issues it resolves are not in Android devices.

If this is needed in the future, it can be brought back in an ABI-safe way.

Bug: 161946584
Change-Id: I06a9e667eb91d6502d040b7ba5db7c43f9ccdcb5
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>