The newer trackpoints from ALPS, Elan and NXP implement a very limited
subset of extended commands and controls that the original trackpoints
implemented, so we should not be exposing not working controls in sysfs.
The newer trackpoints also do not implement "Power On Reset" or "Read
Extended Button Status", so we should not be using these commands during
initialization.

While we are at it, let's change "unsigned char" to u8 for byte data or
bool for booleans and use better suited error codes instead of -1.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>