Having module device table based on PNP id produces the following warning:

  CC      drivers/input/touchscreen/htcpen.o
drivers/input/touchscreen/htcpen.c:50: warning: 'pnp_ids' defined but not used

This happens because it is not a PNP driver, bit rather ISA driver and
pnp_ids table is not used anywhere. To fix this issue let's switch to
DMI-based module table instead,
Reported-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>