Input: serio - remove CONFIG_HOTPLUG ifdefs

Remove conditional code based on CONFIG_HOTPLUG being false.  It's
always on now in preparation of it going away as an option.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>