sensors:max31785-msl: Enable/install max31785-msl package

The max31785-msl application is now a package within the phosphor-hwmon
recipe, so that package needs to be enabled and installed on
`ibm-ac-server` alias of machines which have a max31785 chip. These
machines require that the minimum ship level(msl) be verified on them
using this application.

Tested:
    Built phosphor-hwmon package after enabling max31785-msl package
    Verified application, config file, and service existed in image

(From meta-ibm rev: 33184059fa07ca12e11fb9e8dde2d6a31e1f029e)

Change-Id: I186fb6ca930e4107738d4ed90d31b6233be3d6f2
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>