Input: tsc2005 - don't use work for 'pen up' handling

We do not need process context to send input events so let's switch to
a regular timer. I am going to get rid of taking ts->mutex in
tsc2005_irq_thread() later.

Tested-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>