Input: ucb1400_ts - IRQ probe fix

The UCB1400 driver IRQ probe code fails to find an interrupt if all
the interrupts in the range 0-31 are nonprobe-able. This patch
removes the check of the return value so interrupts above 31 can be
detected.

Tested on InHand Fingertip4 PXA270 board.

Signed-off-by: Vernon Sauder <vsauder@inhand.com>
Acked-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>