Input: omap4-keypad - disable unused long interrupts

We are not using the long events and they produce extra interrupts.
Let's not enable them at all.

Note that also the v3.0.8 Linux Android kernel has long interrupts
disabled.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20210110190529.46135-2-tony@atomide.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>