Input: ti_am335x_tsc - fix incorrect step config for 5 wire touchscreen

Input: ti_am335x_tsc - fix incorrect step config for 5 wire touchscreen

Step config setting for 5 wire touchscreen is incorrect for Y coordinates.
It was broken while we moved to DT. If you look close at the offending
commit bb76dc09ddfc ("input: ti_am33x_tsc: Order of TSC wires, made
configurable"), the change was:

- STEPCONFIG_XNP | STEPCONFIG_YPN;
+ ts_dev->bit_xn | ts_dev->bit_yp;

while bit_xn = STEPCONFIG_XNN and bit_yp = STEPCONFIG_YNN. Not quite the
same.

Fixes: bb76dc09ddfc ("input: ti_am33x_tsc: Order of TSC wires, made configurable")
Signed-off-by: Jeff Lance <j-lance1@ti.com>
[vigneshr@ti.com: Rebase to v4.14-rc1]
Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>