USB: EHCI: remove unused Link Power Management code

This patch (as1622) removes the USB-2.1 Link Power Management code
from the ehci-hcd driver.  This code was never integrated with
usbcore, it is full of bugs, and it was not getting used by anybody.

However, the debugging code for dumping the LPM-related fields in the
EHCI registers is left in place.  In theory it might be useful to see
these values, even though we don't use them.

This essentially amounts to a partial revert of commit
aa4d8342 (USB: EHCI: EHCI 1.1
addendum: preparation) and an almost full revert of commit
48f24970 (USB: EHCI: EHCI 1.1
addendum: Basic LPM feature support) plus its follow-ons.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>