`sicm_avail` and `sicm_capacity` very often wrong

[benbenolson]

Recently, a coworker and I have been working on a high-level feature that requires calls to sicm_avail and sicm_capacity, but these functions are wrong quite often. Because they read a hardcoded 66 bytes into /sys/devices/system/node/nodeX/meminfo, they're wrong when the system has less than 10GB and more than 100GB of memory (which is true for 100% of the systems that we're currently working on). This commit is the culprit.

@calccrypto What was the issue with the previous way of doing it, where you parse for MemFree or MemTotal? I can rewrite this function if you don't want to mess with it, but I don't want to introduce old bugs.

[calccrypto]

I think I was trying to cleanup the code and messed up.