Rescue trollcop drivers

The drivers for the hmc5983 and ms5611 (SPI) were part of PR #674 by @trollcop.  That PR was dropped by @trollcop.  This PR rescue's the driver portion of that original PR.

Note: The driver commits were previously intermixed with other code changes so I've created new commits of a subset of the files but maintained @trollcop as the original author.  The content of the files are unchanged from the original PR.

I don't have HW with these chips so I have not tested these drivers.