Input: move name/timer init to input_alloc_dev()

We want to allow drivers to call input_event() at any time after the
device got allocated. This means input_event() and input_register_device()
must be allowed to run in parallel.

The only conflicting calls in input_register_device() are init_timer() and
dev_set_name(). Both can safely be moved to device allocation and we're
good to go.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>