The following patch changes the way we invert beep bits for the AS99127F
sensor chip. This chip behaves differently from the other chips in that
a disabled bit is 1, not 0. So far we didn't handle that specificity in
the w83781d driver, so it was left to user-space applications to handle
it. For the sake of uniformity, it's obviously better if it's done in
the driver instead (although the meaning of each bit is still
chip-dependant).

I already did a similar change to the 2.4 driver and the sensors
program. I don't think that many user-space application will be
affected, since most of them don't handle the beep mask as far as I can
tell.

This also close Debian bug #209299:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=209299

Successfully tested on my AS99127F rev.1 chip. Aurelien Jarno also
checked that there were no regression on non-Asus chips.