hwmon: Clearly mark ACPI drivers as such

Now that we have ACPI-based hardware monitoring drivers, and we will
start telling users to use them instead of native drivers when I/O
resources conflict, I think it would be good to clearly mark ACPI
drivers as such in Kconfig.

Also, in the case of monolithic kernels, I think the ACPI drivers
should take precedence over native drivers, so they should be listed
first in Makefile.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Luca Tettamanti <kronos.it@gmail.com>