Use standard dynamic sysfs callbacks instead of macro-generated
functions. This makes the code more readable, and the binary smaller
(by about 34%).

As a side note, another benefit of this type of cleanup is that they
shrink the build time. For example, this cleanup saves about 29% of
the lm80 driver build time.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>