Input: ucb1400_ts - enable interrupt unconditionally

Sometimes, when using the touchscreen, it stops working till next restart
and the following message is printed:

	ucb1400: unexpected IE_STATUS = 0x0

The following patch retriggers the touchscreen interrupt unconditionally.
This prevents hanging of the touchscreen in case of bogus interrupt
occurence.

Signed-off-by: Pavel Revak <palo@bielyvlk.sk>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>