jedec_dimm(4): report asset info and temperatures for DDR3 and DDR4 DIMMs

jedec_dimm(4): report asset info and temperatures for DDR3 and DDR4 DIMMs

A super-set of the functionality of jedec_ts(4). jedec_dimm(4) reports asset
information (Part Number, Serial Number) encoded in the "Serial Presence
Detect" (SPD) data on JEDEC DDR3 and DDR4 DIMMs. It also calculates and
reports the memory capacity of the DIMM, in megabytes. If the DIMM includes
a "Thermal Sensor On DIMM" (TSOD), the temperature is also reported.

Reviewed by:	cem
MFC after:	1 week
Relnotes:	yes
Sponsored by:	Panasas
Differential Revision:	https://reviews.freebsd.org/D14392
Discussed with:	avg, cem
Tested by:	avg, cem (previous version, no semantic changes)