Input: ucb1400_ts - allow passing IRQ through platfrom_data

This patch allows UCB1400 to get IRQ GPIO from platform data. In case
platform_data are not supplied or the IRQ supplied in the platform_data
is negative, fall back to the old IRQ detection algorithm.

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>