USB: EHCI: move ehci_update_device() to ehci-lpm.c

In preparation for splitting the ehci-hcd driver into a core library
and separate platform-specific driver modules, this patch (as1618)
moves ehci_update_device() from a couple of platform-specific source
files into ehci-lpm.c.  This is where it should have been all along,
since all it does is call a couple of other functions that are already
in ehci-lpm.c.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>