Devices connected to serio bus are quite slow, and to improve apparent
speed of resume process, serio core resumes (reconnects) its devices
asynchronously, by posting port reconnect requests to a workqueue.
Unfortunately this means that if there is a dependent device of a given
serio port (for example SMBus part of touchpad connected via both PS/2 and
SMBus), we do not have a good way of ensuring resume order.

This change allows drivers to define "fast reconnect" handlers that would
be called in-line during system resume. Drivers need to ensure that these
handlers are truly "fast".

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>