usb-serial: clean up unneeded PM-related fields

This patch (as1551) cleans up the PM-related entries in the usb_driver
structures of the various USB serial driver modules.  Those entries
are now filled in by the usb-serial core during driver registration,
so they don't need to be initialized explicitly in the source code.

The same is true of the one remaining no_dynamic_id entry.

reset_resume remains a small problem, because the serial core doesn't
support it.  The patch ignores these entries.

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