meta-ibm: Add max31785 hwmon config for Balcones

Create the phosphor-hwmon config file for the max31785 for two
single or counter rotating fans to support Balcones power on.
Update the 'CHIPS:p10bmc ' variable in the hwmon recipe to
reflect new file. The max31785 is on I2C bus 7 at address
0x53.

Tested:
* Built firmware image and verified presence of I2C config
  file in the rootfs directory of the image.

Change-Id: I3105e68ee070ab556187f17634a72cb386c6bef4
Signed-off-by: Anwaar Hadi <anwaar.hadi@ibm.com>