input: TSC: ti_tscadc: set FIFO0 threshold Interrupt

Code currently uses FIFO1 threshold interrupt.
since this is a MFD, Dedicating FIFO0 to touchscreen
and making way for other devices to use FIFO1 as well.
The FIFO can be shared between 2 devices but since the
interrupt used is threshold interrupt on FIFO1, we would
end up having wrong interrupts. Hence changing the same.

Signed-off-by: Patil, Rachna <rachna@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>